?
It's to prevent from getting rolecopped by scum basically. Scum teams with a janitor and a rolecop can get an easy fake claim by janitoring someone and claiming their role as one of their own.
I haven't hosted in long time but to me There are many things wrong with that passive wordings which I don't see a host giving it to town.
Your passive says - you are invest immune which cannot be bypassed by any means..
It's blanket immunity covering all aspects which usually is given to roles like GF.
Second, Janitor happens after the kill. So don't think it comes under it.
Third, I checked the wus...all players who got killed flipped with their roles. No one got janitored so far. Why scums won't use Janitor from the beginning if they have it?
Fourth, if you are role cop immune then your passive would clearly state so - you are role cop immune and not you are investigative immune which cannot be bypassed by any means.
A slim possibility that your passive might actually be true is if there is a framer and rolecop in the ranks of scums which I really doubt.