I'm running a sim for HJ vs Btn flat. Specifically I'm looking at J9cc as the button given following action:

Button calls pre, Flop Ts9d5s xx, Td x/xr/Btn call, River 2h overbet from oop and Button is deciding whether to call/fold.

When analyzing the EV of this hand in PIO, the EV of a call on the river is 55.2 and the EV of a fold is 0. PIO is calling 66% and folding 34%. Shouldn't we always call if the EV of a call is greater than the EV of a fold? (Not sure it matters but the pot size is 1294 and the Button is facing a bet of 710). Can somebody help me clear up this confusion?