Chasing electrical gremlins - GFCI outlet puzzle

On our trip at the end of last month, a table lamp quit working. Changing the bulb did not help, but a voltage detector showed voltage present at the base of the socket. I figured the switch in the lamp socket died.

I finally got around to buying a new lamp socket and I installed it today. No joy.

Using an outlet tester on the receptacle showed hot and ground reversed! I checked the breaker panel, and things were wired correctly on that end of the circuit. Some other outlets on that circuit checked out okay so I began to work upstream from the problem.

Long story short, I found the circuit routed through a GFCI outlet in the basement. That GFCI outlet and everything downstream tested “hot and ground reversed.” I pulled the line side of that outlet and found that the power coming in was correct, black = hot, white = neutral, bare = ground. The GFCI outlet was wired correctly, line side and load side. The problem has to be in the GFCI outlet.

After removing the GFCI outlet and connecting the appropriate wires with Scotch locks / wire nuts, everything downstream works okay.

The GFCI outlet does not seem to want to reset. I will replace it.

Also, I think I will re-route some wiring so that the interior outlets that are not near water, etc., are not routed through the GFCI receptacle, as I see no need for that kind of protection.

My question: I expected that if the GFCI outlet tripped, it would “interrupt” the circuit, i.e., break it. Could it have shunted the hot to ground, thereby activating the ground wires downstream, yet leaving the hot wire dead downstream?

I Googled to see how the GFCI outlets work, but came up empty.

Wayne