So I converted all my databases to utf8mb4 including all the fields. But I am still getting this error occasionally.
Illegal mix of collations (utf8mb4_general_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE) for operation '='
I am wondering if all I need to do is change library/XenForo/Application.php on line 712 to utf8mb4.
'charset' => 'utf8'