Dometic refrigerator question

[Katja]

My Dometic DM265RBX refrigerator sometimes stops working when in 120V mode. It then runs fine on LP. Two weeks ago, it ran fine on 120 at the house for three days, then fine on 120 at the first campground for a 3 night stay. At the next campground, on day 2, I realized that it was no longer cooling. Turned it off for about an hour, then on to LP and it started working again. Turned it off for about 15 minutes and then on to 120, but it would not cool (there was a fan running kind of sound however) Back to LP and it worked fine. Left it off when we got home for 24 hours, then on to 120 for 24 hours and it is now 30 degrees and appears to be working fine. I have read some of the articles posted here, watched some youtube videos and know a lot more than I did about this type of refrigeration, but am wondering if my problem is related to the campground electric supply rather than something with my appliance? On our six week out west grand adventure, it stopped working on electric maybe twice during the 26 campgrounds we stayed at. Worked on LP every time. Should I be checking the voltage at the pedestal? If so, for what? This is in a 2011 Coachmen Chapparal purchased used 12 months ago. Thanks in advance - the previously posted refrigerator articles have been very helpful in ruling out 'things'.