Multisite CustomPress 404 errrors

I occasionally have 404 errors when looking at top level Pages (although child pages seem unaffected). This is the primary (and only) domain of a subdomain network installation (4.53)
This is not a live site yet - I'm still trying to test plugins and configurations.
I originally installed the multisite under a different URL and then edited the database to reflect a new. Most of the time everything works fine, but occasionally on this and previous tests I had problems with permalinks. CustomPress seems like the cause of the problems, and is configured to share the same settings across all subsites (even though no other subsites exist yet)

Troubleshooting part 1:
disabled all plugins except CustomPress (1.3.5.8)
deleted all content
deleted all taxonomy
set theme to twenty sixteen
created 2 pages:
/test/
/test/too/
tried each preset permalink pattern
deleted custom post type definitions

Results:
each permalink pattern that includes %postname% remains a problem for the page at:
/test/

each permalink pattern has no negative affect on the page at:
/test/too/

Troubleshooting part 2:
removed all custom taxonomy definitions

Results part 2:
both pages are now loading normally

Troubleshooting part 3:
I have subsequently added one hierarchical and one non-hierarchical custom taxonomy definitions

Results part 3:
both pages are now loading normally

Troubleshooting part 4:
I imported the original taxonomy definitions again
set permalinks as /%postname%/

Results part 4
404 error again for the page at:
/test/

no problem for the page at:
/test/too/

My conclusion is that something within the original set of custom taxonomies is conflicting with the permalinks, but don't know WordPress well enough to be able to troubleshoot further

I have included the exported settings for Post types, Taxonomies, and Fields in the hope that they will help:

// Post Types Export code for CustomPress
global $CustomPress_Core;
$CustomPress_Core->import=array (
'post_types' =>
array (
'phrase' =>
array (
'labels' =>
array (
'name' => 'Phrases',
'singular_name' => 'Phrase',
),
'supports' =>
array (
'title' => 'title',
'revisions' => 'revisions',
),
'supports_reg_tax' =>
array (
'category' => '',
'post_tag' => '',
),
'capability_type' => 'page',
'map_meta_cap' => false,
'description' => '',
'menu_position' => '',
'show_ui' => true,
'show_in_nav_menus' => false,
'publicly_queryable' => false,
'exclude_from_search' => true,
'hierarchical' => false,
'has_archive' => false,
'rewrite' =>
array (
'with_front' => false,
'feeds' => false,
'pages' => false,
'ep_mask' => 0,
),
'query_var' => true,
'can_export' => true,
'cf_columns' => '',
'capabilities' =>
array (
'create_posts' => 'create_pages',
),
),
'cluster' =>
array (
'labels' =>
array (
'name' => 'Clusters',
'singular_name' => 'Cluster',
),
'supports' =>
array (
'title' => 'title',
'editor' => 'editor',
'thumbnail' => 'thumbnail',
),
'supports_reg_tax' =>
array (
'category' => '',
'post_tag' => '',
),
'capability_type' => 'post',
'map_meta_cap' => true,
'description' => '',
'menu_position' => '',
'show_ui' => true,
'show_in_nav_menus' => false,
'publicly_queryable' => false,
'exclude_from_search' => true,
'hierarchical' => false,
'has_archive' => false,
'rewrite' =>
array (
'with_front' => false,
'feeds' => false,
'pages' => false,
'ep_mask' => 1,
),
'query_var' => true,
'can_export' => true,
'cf_columns' => '',
'capabilities' =>
array (
'create_posts' => 'create_posts',
),
),
),
);

// Taxonomies Export code for CustomPress
global $CustomPress_Core;
$CustomPress_Core->import=array (
'taxonomies' =>
array (
'brand' =>
array (
'object_type' =>
array (
0 => 'post',
1 => 'page',
2 => 'attachment',
3 => 'ngg_gallery',
4 => 'ngg_pictures',
),
'args' =>
array (
'labels' =>
array (
'name' => 'Brands',
'singular_name' => 'Brand',
),
'public' => true,
'show_admin_column' => true,
'hierarchical' => true,
'rewrite' =>
array (
'with_front' => true,
'hierarchical' => false,
'ep_mask' => 0,
),
'query_var' => true,
'capabilities' =>
array (
'manage_terms' => 'manage_categories',
'edit_terms' => 'manage_categories',
'delete_terms' => 'manage_categories',
'assign_terms' => 'edit_pages',
),
),
),
'year' =>
array (
'object_type' =>
array (
0 => 'post',
1 => 'attachment',
2 => 'ngg_gallery',
3 => 'ngg_pictures',
),
'args' =>
array (
'labels' =>
array (
'name' => 'Years',
'singular_name' => 'Year',
),
'public' => true,
'show_admin_column' => true,
'hierarchical' => true,
'rewrite' =>
array (
'with_front' => true,
'hierarchical' => false,
'ep_mask' => 0,
),
'query_var' => false,
'capabilities' =>
array (
'manage_terms' => 'manage_categories',
'edit_terms' => 'manage_categories',
'delete_terms' => 'manage_categories',
'assign_terms' => 'edit_posts',
),
),
),
'person' =>
array (
'object_type' =>
array (
0 => 'post',
1 => 'page',
2 => 'ngg_gallery',
3 => 'ngg_pictures',
),
'args' =>
array (
'labels' =>
array (
'name' => 'Persons',
'singular_name' => 'Person',
),
'public' => true,
'show_admin_column' => true,
'hierarchical' => false,
'rewrite' =>
array (
'with_front' => true,
'hierarchical' => false,
'ep_mask' => 0,
),
'query_var' => true,
'capabilities' =>
array (
'manage_terms' => 'manage_categories',
'edit_terms' => 'manage_categories',
'delete_terms' => 'manage_categories',
'assign_terms' => 'edit_pages',
),
),
),
'group' =>
array (
'object_type' =>
array (
0 => 'post',
1 => 'page',
2 => 'attachment',
3 => 'revision',
4 => 'ngg_gallery',
5 => 'ngg_pictures',
),
'args' =>
array (
'labels' =>
array (
'name' => 'Groups',
'singular_name' => 'Group',
),
'public' => true,
'show_admin_column' => true,
'hierarchical' => false,
'rewrite' =>
array (
'with_front' => true,
'hierarchical' => false,
'ep_mask' => 0,
),
'query_var' => true,
'capabilities' =>
array (
'manage_terms' => 'manage_categories',
'edit_terms' => 'manage_categories',
'delete_terms' => 'manage_categories',
'assign_terms' => 'edit_pages',
),
),
),
'phrase_category' =>
array (
'object_type' =>
array (
0 => 'phrase',
),
'args' =>
array (
'labels' =>
array (
'name' => 'Phrase Categories',
'singular_name' => 'Phrase Category',
),
'public' => true,
'show_admin_column' => true,
'hierarchical' => true,
'rewrite' =>
array (
'with_front' => true,
'hierarchical' => false,
'ep_mask' => 0,
),
'query_var' => true,
'capabilities' =>
array (
'manage_terms' => 'manage_categories',
'edit_terms' => 'manage_categories',
'delete_terms' => 'manage_categories',
'assign_terms' => 'edit_pages',
),
),
),
'cluster_category' =>
array (
'object_type' =>
array (
0 => 'cluster',
),
'args' =>
array (
'labels' =>
array (
'name' => 'Cluster Categories',
'singular_name' => 'Cluster Category',
),
'public' => true,
'show_admin_column' => true,
'hierarchical' => true,
'rewrite' =>
array (
'with_front' => true,
'hierarchical' => false,
'ep_mask' => 0,
),
'query_var' => true,
'capabilities' =>
array (
'manage_terms' => 'manage_categories',
'edit_terms' => 'manage_categories',
'delete_terms' => 'manage_categories',
'assign_terms' => 'edit_posts',
),
),
),
),
);

// Custom Fields Export code for CustomPress
global $CustomPress_Core;
$CustomPress_Core->import=array (
'custom_fields' =>
array (
'text_577a6e386de7d' =>
array (
'field_title' => 'Title Headline',
'field_wp_allow' => 0,
'field_type' => 'text',
'field_sort_order' => 'default',
'field_date_format' => '',
'field_regex' => '',
'field_regex_options' => '',
'field_regex_message' => '',
'field_message' => '',
'field_default_option' => NULL,
'field_description' => 'Longer version of the Title to display within the page',
'object_type' =>
array (
0 => 'post',
1 => 'page',
),
'hide_type' =>
array (
0 => 'attachment',
1 => 'revision',
2 => 'nav_menu_item',
3 => 'ms_membership',
4 => 'ms_relationship',
5 => 'ms_invoice',
6 => 'ms_communication',
7 => 'ms_event',
8 => 'phrase',
9 => 'cluster',
10 => 'ngg_album',
11 => 'ngg_gallery',
12 => 'ngg_pictures',
13 => 'lightbox_library',
14 => 'displayed_gallery',
15 => 'display_type',
16 => 'gal_display_source',
),
'field_required' => 0,
'field_id' => 'text_577a6e386de7d',
'field_order' => 0,
),
'textarea_577a78599fb13' =>
array (
'field_title' => 'Related Pages',
'field_wp_allow' => 0,
'field_type' => 'textarea',
'field_sort_order' => 'default',
'field_date_format' => '',
'field_regex' => '',
'field_regex_options' => '',
'field_regex_message' => '',
'field_message' => '',
'field_default_option' => NULL,
'field_description' => '',
'object_type' =>
array (
0 => 'post',
1 => 'page',
),
'hide_type' =>
array (
0 => 'attachment',
1 => 'revision',
2 => 'nav_menu_item',
3 => 'ms_membership',
4 => 'ms_relationship',
5 => 'ms_invoice',
6 => 'ms_communication',
7 => 'ms_event',
8 => 'phrase',
9 => 'cluster',
10 => 'ngg_album',
11 => 'ngg_gallery',
12 => 'ngg_pictures',
13 => 'lightbox_library',
14 => 'displayed_gallery',
15 => 'display_type',
16 => 'gal_display_source',
),
'field_required' => 0,
'field_id' => 'textarea_577a78599fb13',
'field_order' => 1,
),
'textarea_577a7803f2926' =>
array (
'field_title' => 'Related Links',
'field_wp_allow' => 0,
'field_type' => 'textarea',
'field_sort_order' => 'default',
'field_date_format' => '',
'field_regex' => '',
'field_regex_options' => '',
'field_regex_message' => '',
'field_message' => '',
'field_default_option' => NULL,
'field_description' => '',
'object_type' =>
array (
0 => 'post',
1 => 'page',
),
'hide_type' =>
array (
0 => 'attachment',
1 => 'revision',
2 => 'nav_menu_item',
3 => 'ms_membership',
4 => 'ms_relationship',
5 => 'ms_invoice',
6 => 'ms_communication',
7 => 'ms_event',
8 => 'phrase',
9 => 'cluster',
10 => 'ngg_album',
11 => 'ngg_gallery',
12 => 'ngg_pictures',
13 => 'lightbox_library',
14 => 'displayed_gallery',
15 => 'display_type',
16 => 'gal_display_source',
),
'field_required' => 0,
'field_id' => 'textarea_577a7803f2926',
'field_order' => 2,
),
'text_577a7a5d30729' =>
array (
'field_title' => 'Media',
'field_wp_allow' => 0,
'field_type' => 'text',
'field_sort_order' => 'default',
'field_date_format' => '',
'field_regex' => '',
'field_regex_options' => '',
'field_regex_message' => '',
'field_message' => '',
'field_default_option' => NULL,
'field_description' => '',
'object_type' =>
array (
0 => 'post',
1 => 'page',
),
'hide_type' =>
array (
0 => 'attachment',
1 => 'revision',
2 => 'nav_menu_item',
3 => 'ms_membership',
4 => 'ms_relationship',
5 => 'ms_invoice',
6 => 'ms_communication',
7 => 'ms_event',
8 => 'phrase',
9 => 'cluster',
10 => 'ngg_album',
11 => 'ngg_gallery',
12 => 'ngg_pictures',
13 => 'lightbox_library',
14 => 'displayed_gallery',
15 => 'display_type',
16 => 'gal_display_source',
),
'field_required' => 0,
'field_id' => 'text_577a7a5d30729',
'field_order' => 3,
),
'text_577a7ac207a16' =>
array (
'field_title' => 'Call to Action',
'field_wp_allow' => 0,
'field_type' => 'text',
'field_sort_order' => 'default',
'field_date_format' => '',
'field_regex' => '',
'field_regex_options' => '',
'field_regex_message' => '',
'field_message' => '',
'field_default_option' => NULL,
'field_description' => '',
'object_type' =>
array (
0 => 'post',
1 => 'page',
),
'hide_type' =>
array (
0 => 'attachment',
1 => 'revision',
2 => 'nav_menu_item',
3 => 'ms_membership',
4 => 'ms_relationship',
5 => 'ms_invoice',
6 => 'ms_communication',
7 => 'ms_event',
8 => 'phrase',
9 => 'cluster',
10 => 'ngg_album',
11 => 'ngg_gallery',
12 => 'ngg_pictures',
13 => 'lightbox_library',
14 => 'displayed_gallery',
15 => 'display_type',
16 => 'gal_display_source',
),
'field_required' => 0,
'field_id' => 'text_577a7ac207a16',
'field_order' => 4,
),
),
);