Does anyone know if the fuel tank vent is one way only? Mine takes air in to displace the fuel as its used to prevent pulling a vacuum. It does not vent pressure out of the tank and if the Rzr flipped wouldn’t allow fuel out. I have tested this with low air pressure. Air blown back into the tank via the vent tube just pressurizes the tank and doesn’t dissipate until you remove the gas cap. Air blown into the tank will not go out the vent tube. The tank again stays pressurized until you remove the cap.
This caused my Rzr 1K to stall at idle at 12K elevation twice. Once you relieve the pressure by opening the cap all went back to normal until I went to idle again at the higher altitude. It ran fine so long as I get going and only stalled at idle.

Utah RZR Rentals