Final report:
Turns out dirt/mud got into the clutches and was not letting them engage completely, so the belt was slipping.
I'm wondering how the mud got there though, I have not had it deep enough to have water up to the CVT intake, so I'm left with two possibilities, in my mind.
1) The mud got in through the intake from pressure washing the seats and such.
or
2) There is a bad seal/leak somewhere letting dirt into the clutches.
Really hoping it was option 1 as that is easy to solve