You can check the basics like the metal sensor bar, bowden cable & height counter for psychical damage.

I would disconnect the battery then check the electrical connectors at the height counter assembly.

If you had a BT CAN service key you could have looked at the diagnostic screen & see what the height counter channels & sensors are doing as you operate the truck.

FWIW: Since the RRE first came out back in 2009, ive only ever changed 1 height counter for an electrical fault - there normally bulletproof.