Pretty sure the answer is "no" but I'll explain more what I was wondering.

Assume "arse" and "anal" are both on the bad and that underscores are treated like irrelevant whitespace.

Arsenal

A___nal

A______

You mean "arse" and "enal"? So basically overlaps? That's a good question, I'm not sure what happens there, I think the first ligature "wins".

Yeah, if you type "cuntits" it only censors "unt".

No. I mean first the "arse" rule is applied, and then the "anal" rule (because this didn't exist previously and because the blanked out letters are ignored) is applied next

Oh, I see. No, that's not how ligatures work. I also don't see why A___nal would be censored, it's clearly not intended to be a curseword.

Just running with the idea expressed an a parent comment above. I think neither "anal" nor "arse" should be censored