Anyone else have trouble with HF - tripping GFCI in my garage when
keying
the mike.

An interesting tale of GFCI and RFI. Square D was/is a manufacturer of those
little devils. In manufacturing they had a test table where they took
representative samples of the weeks manufacture and ran them under load for
some period of time. These would operate satisfactorily for some extended
period and then the first of the week they would find a large failure rate.
At times, as much as 50 percent of the run had "failed".

Eventually, they found that the plant closed for the weekend, and the guard
in making his rounds would check in on his walkie talkie at a reporting
station located adjacent to the test table. The miniscule amount of RF would
trip those suckers and caused Square D to incorporate some RFI protection.

I have tripped mine causing the street lamp to fail (among other circuits)
but only when running high power on 2 meters. (KW level) If you're failing
yours, it's most likely quite old, either manufactured before they
recognized the problems, or having failed whatever protection that was built
into the module. Would suggest that replacement with a new one from your
local electric supply house will cure the problem.

W4ZCB