Well, in my world at least, it's never really helpful for a vanilla townie to claim freemason since it provokes the real freemason to counterclaim just causing conflict. Hence if a person that has claimed freemason dies as a townie I would just suppose they actually were the freemason.
And if they die as a wolf... well even more obvious.
That's the assumption I'm going off of. And with that in mind I really don’t see a scenario.
I know... strategies where a townie falsely claims freemason and the real freemason goes along with it and doesn't counterclaim etc. etc. .... in reality I just don't think thats helpful.. even less since we can't tell after the false freemason has died. So that's nothing I would ever recommend doing.