[Hummingbird] Issue found by Liquid Web - Hummingbird

In looking at the logs for mydhea.com I am seeing a few errors but one fatal error specifically:
12-Nov-2018 17:13:29 UTC] PHP Fatal error: Uncaught Error: Call to a member function purge() on null in /home/s7/html/wp-content/plugins/wp-hummingbird/core/modules/class-module-page-cache.php:1127
Stack trace:
#0 /home/s7/html/wp-content/plugins/bb-plugin/extensions/fl-builder-cache-helper/plugins/hummingbird.php(10): WP_Hummingbird_Module_Page_Cache->clear_cache()