That's something they've acknowledged too, and had planned on a "Bullshit of Bullshit" finale:
"We promised to do a Penn & Teller: Bullshit of Bullshit! show as our last show in the series, but we walked away for a better deal and didn’t know when we did our last show that it was our last show. We still have hopes of going back and fixing some stuff about climate change, weight loss, secondhand smoke, and other things..."
"We promised to do a Penn & Teller: Bullshit of Bullshit! show as our last show in the series, but we walked away for a better deal and didn’t know when we did our last show that it was our last show. We still have hopes of going back and fixing some stuff about climate change, weight loss, secondhand smoke, and other things..."
https://www.google.com/books/edition/_/guYlDwAAQBAJ?hl=en&gb...
Overall though I think they had a pretty good track record and seem to be forthright about things they messed up.