Sitting at the gate setting up and both the DH light on the artificial horizon and the DH light on the radar altimeter are flashing intermittently. Different durations between flashes, different durations of being lit.

I tried setting the DH to 200 feet on both the captain and FO side radar altimeters. That seems to have cured the flashing but the FO's DH lights stayed on until I clicked repeatedly 5 or 6 times in rapid succession.

I got this too

I'll pass this along to the team, thank you

While I don't have a stream recording of it, my last approach I noted (or seemed to think so) that the DH light was illuminating and extinguishing on its own on my final approach and it coincided with the altitude callouts (to which there were none audibly heard).

I'm wondering if these are somehow being intermixed.

Yes DH lights flash intermittenty on the ground, even after a reset, and can arbitrarily flash on descents too even well above the descision height. To the extent that i'm not sure they function at all as intended. I'm always havnig to reset them.