I fought this issue a ton, and the only fix was GLM led boards (transmit and receive) and making sure they were wired correctly and functioning properly. Once this happened, issues fixed, and game now plays flawlessly.
I had same issue where only 3 of the 6 were working, this after I was sure that all 6 were working, turned out a small disconnect in on of the connectors on transmit board happened when I was installing receiver board.
Get all six of those working and retest.
Good luck!