I recently noticed that my nextcloud instance was missing photos. I have the android app set to automatically upload my photos. When I need to clear up space on my phone, I make a separate backup (because I’m a paranoid SOB and hard drives are relatively cheap). I noticed that nextcloud auto upload missed about 10% of the photos. I’m not going to bash the nextcloud devs, as I recognize that I am using a free product and am owed nothing, but I’m making this post so others are aware of this risk. Apparently I’m not alone https://help.nextcloud.com/t/android-client-does-not-auto-upload-all-images/216849/14
Weird coincidence that the exact reason for this thread is addressed in https://github.com/nextcloud/android/releases/tag/rc-3.35.0-01. RC2 was just released yesterday.
Yes and no, there have been issues with the android app for a long time. Some of it was Google and some the way it would detect files, it just happens that I posted the GitHub issue.