If sometime works fine and sometime not I would suspect a bad/loose wire connection. This is not likely but is a possibility, It may seem odd but car voltage can effect the electronic in a car. I would say while the car is running check the voltage at the battery. It should be showing over 13.7V because with the car running it will be reading the voltage put out by the alternator. Depending on the vehicle I have seen them put out 13.7 to over 15 volts.

Some link below dealing with cluster
https://www.bing.com/profile/history?FORM=EDGEHS&fsi=1
https://www.youtube.com/watch?v=ar_ADSramuk
https://www.youtube.com/watch?v=C2piBMU8v7U
https://www.lifewire.com/gauges-in-car-not-working-4140224
https://www.youtube.com/watch?v=zvuDVdx_Zjo