Hello,
While the internal value for the "ajax custom field" is an array of values (one for the filename and another for the security check) ; the data stored in the database is just the filename.
So, I am wondering how the field has been edited because you should have that in your database, unless the saving is made regardless of the custom field system ; that the raw data is stored in the database and the custom field system is not called to perform the various "checks" and the adjustment of the data before it is saved.
I gave you a temporally solution, as explained.
I told you that we still need to understand
how the data is stored ; so we need to have details, information, workflow ; something to let us understand what is happening and also reproduce the issue in our end.
Regards,