Best guess, Neutral (white) and power (black) A/C lines are reversed. Either at the plug, plug source or the breaker (fuse} box.

Howdy
Any updates ?
Have you gotten it figured out ?

Houston We found the problem…
it was sooo simple……
The extension cord we were using had
ground (round) pin missing.

We used a newer one (because of another reason)
with the all 3 pins and it stopped shocking me.

mystery solved without even trying..

Is your home power cord two or three prong?
Sounds like your home connection or cord is bad.

Walt R.

If you were getting a shock without the ground terminal a GFI would probably be tripping, time for further investigation. JMO

It was connected with a regular orange extension cord
just to keep everything working and fully charged,
after it was replaced with a new one, it stopped
shocking us.(the old extension cord had the round
ground prong missing)

Thanks