@voschix Thanks for reporting this issue.
Mapillary App 5.3.7.2 supports storing images into SD card. I’ll check this out with our Android Developer. Do you see any prompt message when you try to save your images to SD card? If you can share screen-recording to the support, it might be helpful to debug this issue.
Mapillary App does not support accessing imagery when the phone is connected via USB. You can only access images by inserting your SD card into your PC.
I’d recommend you to log out from your account and login again before re-uploading them, this should help.