Annoying GFCI trip

[Mark Forest]

In my new rental property there is a GFCI outlet in the living room. This is on the same circuit as the bathroom fan and the light in the shower stall. This living room wall is on the other side of the bathroom. When I first got the property every time I turned on the fan it tripped the GFCI and thus shut down the fan and the living room outlets. The fan did not vent to the outside so I just got a new fan and vented it out the wall as it should be.

It seemed to all work fine, but occasionally there is a problem. Sometimes when I turn the fan on it is all good, but the GFCI trips when I turn it OFF. First I do not even know why there is a GFCI in the living room, and second I do not know why turning a new fan off would trip the GFCI. I was thinking of just eliminating the GFCI and installing a normal outlet in the living room. Can any of you think of why the original owner would have put this GFCI there and is it okay to just simply switch it for a standard outlet?