GFCI tripping

I have added onto a circuit [temporarily] and found that the GFCI in the bathroom will intermittently trip. I included a configuration of the circuit and not sure where to physically begin troubleshooting the problem.

The problem is about every fourth time I turn on the garage lights the GFCI in the bathroom will trip.

The circuit goes from the panel to garage/stair lighting to deck GFCI*, to kitchen lighting and living room fan -- I have temporarily added a bathroom and bedroom to the circuit** [until I can get a new circuit in place].

Doesn't the GFCI sense and protect the part of the circuit that is further from the panel?

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* may be bad because the test button does not seem to work.

** this is actually the way it was set up when I moved in [12 years ago] and was that way for at least a year with no problems.

 

Kitchen needs to be a 20 amp dedicated circuit. Bathroom needs to be a 20 amp dedicated circuit. Bedroom should not be on this circuit. This is such a mess I'd just start running new circuits.

 

Even the garage should be on it's own 20 amp. with GFI on the outlets.
Kitchens now need at least 2 circuts, 20 amp and be GFI on the outlets.
Extra runs for the microwave, dishwasher.