Credit fields missing from media gallery

The fields to input media credits is no longer showing up in my media gallery when I “add media”. The only plugin I’ve added was a required plugin for my most recent theme update. I deactivated it and the fields are still missing. WordPress updated again as did my theme, could either of these have removed the fields? And what can I do to get them back? The information is still there for all the media credits I’ve added in the past (the fields are missing from those too but the credit appears on the posts) but I can’t add credits to new media.

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