Had that on my BBQ trailer. First, it probably only happens when you are connected to shore power, right? If you haven't changed anything (receptacle wiring, power cords or wiring on power cords), then the next question is - does it happen *wherever* (not just home) you connect to shore power? If so, then check your power cord first, then the receptacle on your trailer, then the house receptacle. When you check the male/female connections -Are there any burn marks? That's often a telling sign!
I'd open both ends of your power cord and look for a disconnected ground in the cord wiring. Just to be safe, I'd disconnect, clean (if necessary), and reconnect the wires in your cord. Make sure the color codes match too!
When you check your receptacle boxes - first on the trailer, then on your house - also open, check/reconnect, wires.
My BBQ trailer was wired wrong. But, afterwards, I also had a time when connecting/disconnecting the power cord loosened up the connections in the cord and the ground was loose. I noticed it every time I went to check tire pressure! I'd touch the valve stem and get a very minor tingling shock.
It's usually the most obvious place - the cord and its connections.
Good luck!
Bill