When verifying an S/MIME signature which is invalid (maybe also other cases with not fully valid signature, I did not test other variants), "Save all" and "Abort" is offered, instead of "OK" to acknowledge the message.

Pressing the Save button or "Return" will result in the creation of an empty file names test.txtBerta.

Here is the signature file for ease of reproducing this (was created with a faked-system-time before the creation date of the certificate). The certificate is from the standard test set.