save button grayed out randomly

Hello wordpress community,

we are facing the issue, that the save-button in wordpress is sometimes greyed-out (and stays that way). As far as we observed this, this usually happens on the auto-save.

I am aware, that the usual reason for this would be errors in the code, but there are no errors logged in the fpm- or apache-logs. There is also no indication of a timeout (ie no 408 response code).

The wordpress instance currently has 512 MB of RAM and does not use all of it. It also has more than enough CPU-Power.

My assumption is, that there is either a timeout on the auto-draft-saves or an error of some kind, that does not get logged.

So how would i be able to confirm this/find the error? turning on WP_DEBUG is not an option tho, as there is too much traffic on this backend.

thank you,

best regards,

scones