Please check that the compressor starts up and shuts down normally.

Startup should be with open valves to make it easier for the compressor to startup.

Is the pressure setting below the maximum allowed setting?

When stopping the compressor, do you close all outlets first and let it run idle for a minute?

Maybe the coupling gets to much stress because of this.

It's a guess, hard to say from here.

Good luck and hope I was of some help

Cas