Subject Line regexp bug?

[Firewalk]

Yesterday we received an email ticket from one of our customers. The subject line in the message was a single question mark. This caused me a good bit of grief as it appeared to break ticket followups and responses. It wasn't a total breakdown but it did spawn a large number of new tickets all containing the same data.

I'm setting up an isolated environment that's an exact clone of our production setup in an attempt to replicate this. Has anyone encountered this previously? We are running 3.0.7 with a mysql backend.

-M