Inspected a condo corner unit. as walked up to the door came to my first receptacle opened it saw smoke stain it was a GFCI stuck the tester in it. It wouldn’t trip, but would trip with its own test button. This same receptacle is in line with the patio’s none GFCI. When testing the patio’s receptacle it would trip the GFCI at the front door properly. Inside the condo there was a number of GFCI’s, only one in one of the bathrooms would trip properly. All would trip with their own trip test buttons. IN the Kitchen no GFCI’s one receptacle showed an open neutral. All other receptacles showed they were wired correct.

Any good reasons as to why?

Thank You in advance

Some one does not know the differance between line and load. They are wired wrong

how old of a condo?

if there’s older 2 wire wiring mixed in, that could explain since ungrounded gfci’s can’t be tripped by most basic testers, but can by the test button.

condo is listed 12 years but hot water tank says its 14 years old.

what James said.

It is very unlikely that there are 2 wire circuits in a 12 or 14 year old building. Line-load reversal will have all the symptoms described above. An electrician should take a look at it.