nav_menus breaks with wp-texturize error

I'm baffled.

I've been working on a Product based child theme and making adjustments to the top level navigation. Had it all dialed in and working sweetly until the other day I signed on to find the following warning message just below my menus:

Warning: preg_split() expects parameter 2 to be string, object given in /path/wp-includes/formatting.php on line 34.

My menu system functions (has been anyway) like the buddypress.org site where top level links in one line bring up lower level links in the next line on hover or click. Top navigation link 1 calls up a text line in the submenu. Top navigation links 2, 3, 4, and 5 are each assigned a nav_menu whose items can be populated from the backend and then show up in the submenu. Top navigation link 6 calls up buddypress links in the submenu.

I've looked through all my code and nothing obvious stands out. I've also tried to access the menus backend to see if there might be something amiss but I get the following error message:
Catchable fatal error: Object of class WP_Error could not be converted to string in /path/wp-includes/formatting.php on line 433

Baffled. Any ideas?