Buzzing on 1 random fret: Bad fret?

[EADG mx]

One of my basses is buzzing very badly on the 1st fret G string to the point where I can't stand to use this fret in my playing.

I don't think it's a case of setup since the rest of the strings are fine, and loosening the truss rod hasn't helped.

I don't think it's the saddle height as the rest of the frets are fine, even in the lower positions.

I've tried raising the string in the nut to see if it was being caused by the nut slot being cut too low - also didn't help

It's not being caused by a bad string as it's done this with various sets and brands of strings


any ideas?

[202dy]

Assuming the G is the high string, the fret may be "popped". Checked to see if the fret is seated in the slot by sliding a .003" feeler gauge between the fingerboard and the fret.