That DD bet was so bad because it did nothing to improve her position and the only impact on the game would have been if she got it wrong it might have been a runaway.
Parkinson’s can cause fatigue. This is total speculation but perhaps he used enough energy on the first show that he couldn’t rally for the next one.
Especially when you remember that they're pretty much filmed back-to-back, unless your first game happened to be a Friday show.
I just recently learned that Wheel of Fortune films shows just 34 days a year. That’s just incredible to me. And of the thousands of shows she’s done, Vanna has never worn the same outfit twice, which is more incredible.