I did see this post (LZW31-SN: Very bad flickering after updating to 1.47 (otz and bin)) but I didn’t update any firmware.
This is interesting, though (I think). I just tried turning “Smart Bulb Mode” (parameter 52) ON (it was and has been off) and now when I turn the light on it only flashes once quickly and then turns off, AND in Home Assistant the UI switch turns off, too!
I’ve disabled all the Node-RED flows, so I don’t think that’s a part of the problem.