'Missing media files' when I haven't moved the media at all.

I edited a video using video clips from my Apple photos album. The next day it said the media was missing (even though I hadn't moved it). I imported all the clips in again and redid all the editing, but then when I reopened the project the next day, it was again saying all the clips are missing, despite yet again not having moved anything. 

I can 'locate' them all individually but it won't then apply that to all of them. My one idea is that it seems in Apple photos album I have older photos with the same file name. Eg. there are five photos labelled IMG_4122 from different time periods. COuld this be what is confusing Adobe, and if so how to fix it? The only thing is, I've been using Adobe for years and using videos from the Apple photo album and have almost never had this problem. 

Thanks for any help!