Root causes:
the dim zones are not wired correctly
the dim zone is broken in the PHD
the fixtures were not programmed to dim to off
Steps:
Ensure that the fixtures are wired over to purple correctly
Check that the circuit makes it to the first fixture from PHD
Check voltage at the 0-10 controller on the PHD, seeing 1.3V at 10% and 9.7V at 100%, so lights SHOULD be dimming, as they do elsewhere onsite.