User blog comment:ToyGoldenFreddy2/I Can't Make A Pasta/@comment-25428589-20150520143009/@comment-25428589-20150520143944

Yup, filter 3, if my memory serves me correctly.

It disallows certain punctuation for a couple of reasons. 1: Periods in titles are almost always not in adherence with our style guide. 2: Punctuation (i.e: question marks) is used in URL syntax (for example: "?action=edit") and including them in titles can make it difficult to navigate to a specific page via the nav bar (I think)