Here is a picture of my old thermostat. To my knowledge it does have a heat pump.
i have my nest wired up with that brown wire on W and the clear wire on the left on W2.
I have to reiterate that although this picture makes those wires look orange and white, they are not. The W wire is brown and the W2 is clear.
my unit is on. It states the wiring is correct, however it will not blow cold air.
Thanks for reaching out. You mentioned that yo have a heat pump. I would suggest resetting your Nest Thermostat and put the brown wire to the OB terminal and the white wire to the W1. Configure your Nest Thermostat as a heat pump and let us know the results.