Pizza Hut had a 1984 patent for a mobile delivery/kitchen truck that would cook the pizza en route to the customer.[1] Zume's patent even cites it[1]. Just skimming over both filings, I'm kind of surprised it was issued in the first place.

0. https://patents.google.com/patent/US4632836A/en

1. https://patents.justia.com/patent/10140587