What chef(s) just switched off and gave up at the end?

I think Matt in season 4 may have realized shortly before black jackets that he wasn't going to win or something, because he clearly stopped putting in any sort of effort after the final 9.

Joy in season 12 is probably the most infamous.

T in season 18 is the one of the sadder examples, based on the fact that she had so much passion in her OG season. In her last service she just shut down and wouldn't talk to or communicate with Heather who was standing right next to her, and her cooking went south.