So, I just ran a new Small Applicance Branch circuit into my kitchen. This is a very strange situation, may just be a faulty GFCI, but the second I plug my tester in to this one outlet the GFCI trips. I don't even have to hit the GFCI Test button. I can plug anything else into this outlet without any issues. I figure it was the tester, but I can plug the tester into any other GFCI outlet with no issues. Those only trip when I hit the GFCI Test button. Its only this one outlet and only this GFCI tester that trips it. I then took a different GFCI outlet I have laying around and wired it in and it works fine in that location with the Outlet tester I have. Gonna buy a new GFCI, but curious if anyone else has seen this or knows what would cause it. Gotta buy a new one because one I have laying around is brown, not white.