I am familiar with Meta's interviewing policy, which proscribes LC "hard" type problems. I don't know the contents of every single interview, obviously. Your interviewer(s) violated explicit policy if you were given LC hards.

In a way does it matter? The interviewers aren’t making the final decisions and the actual hiring committee aren’t stupid and should be able do some basic normalization.

I think it probably matters to the individual interviewees and also matters to the hiring committee because it reduces the quality of the hiring signal.

your interviewers gone rogue theory is hard to accept. Many many people have consistently been getting 'LC hards `for years`.