chances are, this rv park or campground doesn't get much use on the 50amp service, which is mainly for larger rigs, so the ants have taken over... it happens a lot.
some inverters do cause flickering, mine does from time to time, mainly noticeable on the fridge light, but only when on the inverter only.
'14 Palazzo 33.3 bunkhouse 34' diesel
KingTailgater2 Dish HD, 100w/5a SOLAR, BlueOx
100,000+mi since '14 - US, Alaska, Canada.... formerly Georgia, then NorthCarolina, now Alabama : )