Wondering if anyone has ever had issues with the adsens people with respect to mfa site with traffic coming (exclusively) from youtube.

They don't have anything against that, do they?

Google has problems with mfa sites themselves.

Yeh. Google likes to come with the ban hammer after MFA sites.
Youtube traffic should rather be used on cpa or sth else makes more money anyways.

To your Question: Nah they don't care. There's no real reason to care cause even if the traffic your sending is low quality it's not like it's fake traffic. It just doesnt convert very well but so does tons of other traffic.