I’ve noticed recently that photos taken in “portrait” mode on my Pixel 3 disappear after Backup. This doesn’t affect videos or photos taken in “standard” mode.
They’re not being deleted from the device as I can locate them using the file picker, but they can no longer appear in Google’s Photo app once they’ve been backed up to my NC server. That being said it may very well be an issue with Google’s Photo app, but I thought it would be worth mentioning in case anyone else noticed any similar behavior. Auto-Upload settings are set to retain photos on the device btw.