Low voltage, low voltage, low voltage is my vote. Intermittent issues due to low voltage was common. If I wasn't an ET I probably would not have chased it down. Connected to shoreline with batteries full it worked fine. Generator running and things were fine. The very long run of the DC wire caused about a 2 volt drop. When the batteries were not being charged that dropped the voltage below the level the dish wants.
Since I have an inverter a simple power supply cured the problem. Once the dish is locked on simply turn things off.
Make sure your rv is level and not one twig is in the way.
