depending on the dogbone your using to go from 240V 50A to 120V you could end up with a GFI that trips. A 50A service is two legs of 120V. And depending on how you go from the 50A/240 to 120 you could either end up with only one leg powered or the two legs tied together. and how it ends up getting configured can be incompatible with a upstream GFI outlet. GFI outlets will trip if they see ground/neutral bonding downstream or some aspects of a 240 trailer to 120V trailer adapter. In fact some of the 50A/240V to 30a/120 adapters will say NOT compatible with GFI outlets.