whatever Opencamera is querying within MainActivity.java: onResume() is coming up short. I’d look at 3 places:
!getStorageUtils().getLastMediaScannedHasNoExifDateTime()
...
Uri check_uri = getStorageUtils().getLastMediaScannedCheckUri();
...
applicationInterface.getDrawPreview().allowGhostImage();
Do you strip exif times from photos at creation?
There’s a report similar to yours, but there the thumbnail is misleading: https://sourceforge.net/p/opencamera/discussion/qa/thread/7e3c506d1d/