@KevinTheJedi
I don't think it's a bug, otherwise I'd be able to replicate the issue.
We only display the Agent Signature if this returns data $thisstaff->getSignature(). So, go in the database, go to the ost_staff table, find your account, and see if there is a signature record with data. If so, paste the content in a codeblock here so I can attempt to replicate.
Sorry, read this wrong...too early in the AM lol SO the issue is actually that your Department is Private. If you set the Department to Public it will allow you to append the signature.
Cheers.