Files app caching SD card, no longer reads SD cards

I use an Apple card reader to get photos/videos off my camera. Currently on iOS 16.3.1 and recently, the Files app has been showing an SD card even when one is not inserted - and no longer sees files on any SD card. When an SD card is inserted, the Photos app will show the Import tab but upon selecting Import it thinks all cards are empty. The exact same cards and adapter work on other peoples iPhones, the problem is the Files app caching an empty SD card and refusing to read anything else. I have deleted and reinstalled the Files app and that makes no difference. Any ideas other than factory resetting the whole phone for a bug that may reoccur the next day (ie a fix or workaround rather than the nuclear option)?