Got some time today to disassemble the connector - simple really. The white/yellow plastic part lifts out, then you can release each of the connectors. I bent the loose connector socket a bit to tighten-up the connection to the switch, re-assembled, and all is good. I'll check it periodically, but it appears that the socket on one of the leads was a not a tight fit on the tab on the inertia switch, probably causing it to heat-up and resulting in the intermittent connection I was seeing. The connector didn't look bad, but it was clearly getting hot. All good - at least for now!

The yellow plastic internal part lifts out - small pick and it comes right out: https://photos.app.goo.gl/b4pH4nPn4ERcHx8H9

Then the two connectors can be released with the "prong" on each holding them in the plastic holder, visible on lower left side of each in this pic: https://photos.app.goo.gl/FYReWjjyWioKgase9