An internal message bug regarding Enable Akismet

I've just discovered an odd bug.

I turned on the Enable Akismet within the Security tab of the Settings menu.  And after a few days have been told that people with FireFox couldn't message each other using the internal mailer.

I thought this was odd since I sent a message on Chrome.

But my member copy & pasted the error, it said API everywhere.  I realised what it was, turned it off, and now the member can send messages again.

Has this 'Enable Akismet' button every thrown up bugs before?

I've not seen this before,

Have you checked the API key?

Also if you have a screenshot that would be good to see

I've never used it before.  I've tried using this API before and even bought a module, but never ever got it to work.  I thought I did recently.  Guess I'll never use it.

No screenshot, and copying & pasting the info will take a while.