We added an Airport field (selector drop-down) to the user profile pages and this has caused fatal memory error when going to any pages with this field. This Airport field lists over 600 airports in the USA.
We upped the php.ini memory_limit to 512M but that doesn't help.
Update: Found problem. Had a few single quotes (Martha\'s Vineyard ( MVY)) that need a backslash... (Also, found that there can be a max of 65,535 elements.)
The things we learn....