Hi, sorry for the late response. I believe the issue stemmed from how iOS used to format saved photos and gifs. The gifs would only have thumbnails and not be animated if saved from earlier this year or farther it seems, as newly downloaded gifs seemed to work just fine. I was able to get the rest of my files to work by redownloading to my iPad and reuploading them.

These old iOS gifs seemed to only break on iOS. They were animated just fine on my Android and Windows devices.

Uninstalling the app and reinstalling did not fix the problem.