Every acting credit on a TV episode is appearing as a "Self" credit

Hello ladies and gentlemen,

Anyone know why every acting credit for the latest Family Guy episode are, for whatever reason, "self" credits?

It's most obvious on the pages for Glen Powell and Derek Jacobi, given they have no other Family Guy credits.

I looked over the page and don't see any reason to think these should all be appearing under "Self".

I think maybe because it has the tag "TV special"? But obviously it's not that kind of documentary/special.