[bsperka]

When the car is unlocked, the unlock switch on the hatch doesn't unlock the hatch. I can only unlock it using the key fob for the hatch and then using the hatch unlock switch. This times out after 30 seconds.

To me, this indicates that the circuit is ok, except that the BCM isn't recognising the signal from the latch switch until it receives a signal from the fob as well. Any thoughts, other than faulty BCM, on what could be causing this?

[Shambles]

You could try a "cold reset" of the BCM by unplugging the battery -ve for 30 mins.