Setup for the bug: Because I use automatic PGP on unencrypted incoming mail provided by the paid e-mail provider I use, I have to disable DKIM checking through the addon itself because the automatic encryption breaks the signature. I therefore have to rely on DKIM Verifier displaying the results of the "Authentication-Results" headers for me. My usual developer e-mail is forwarded through a custom SMTP that I run that adds DKIM check results, and then ends up at an SMTP by a standard paid e-mail provider that also adds DKIM check results before applying Auto-PGP. You can see both of these Authentication-Results headers in the chain below, the lower one being from my forwarder SMTP.

Expected result: As soon as DKIM Verifier finds any Authentication-Results headers somewhere in the entire chain that say "dkim=fail" or "dkim=none", even if that may also trigger on a spoofed fail result attached by the sender to the return path, that should lead to a fail being displayed.

Actual result: As soon as the top-most Authentication-Results header is present and mentions DKIM, DKIM Verifier seems to display "Valid", even if that very top-most header says "fail". This is with local DKIM check disabled, due to above reasoning.