I give this high priority because for some users this might result in data not visible. My first step here will be just looking at the code to check if all error paths are properly handled, afterwards it might get a lower priority.

When decryption succeeds we should always show content of a message even if verify fails. I'm pretty sure the code already intends that but reports in the forum seem to indicate otherwise.

https://wald.intevation.org/forum/forum.php?thread_id=2259&forum_id=21&group_id=11