Similar to these other threads, but I don’t think the same.
https://forum.inaturalist.org/t/wrong-photo-displayed-after-selecting-reordered-photo/33395
https://forum.inaturalist.org/t/android-workflow-crop-photo-and-make-first-make-you-lose-the-cropped-photo/41788
https://forum.inaturalist.org/t/android-deleting-the-last-photo-of-a-set-of-3-removes-also-the-already-confirmed-crop-of-first-photos/25715
I haven’t ever noticed this problem, but I think that’s because I drag the photos to the front instead of selecting “Make first.”