Is it possible to suggest that the devs add a check in cache.php to make sure that the $wp_object_cache variable is an object before trying to access it?
There is a routine error that crops up on line 93 of cache.php that occurs because $wp_object_cache is not instantiated when it is attempted to be accessed.
I've had my site come crashing down several times this week because of this fatal error. Perhaps something like:
if (!is_object($wp_object_cache)) {
return false;
}
return $wp_object_cache->get($id, $flag);