I agree that they should work with the generic Zigbee dimmer. Based on the raw description being missing, I suspect the initial join didn’t complete fully causing the devicetype code that pulls the endpointId dynamically to fail. It simply can’t find the endpointId properly, which is why the hardcoded endpoint works.
I’ve seen it happen in several threads with unsupported Osram lights and a report of the Kudle hue clone. Unfortunately, ST support understandably won’t be much help because the devices are not officially supported. Usually the users have reported trying to reset and pair again with no success, so I’m happy to try and get someone that works even if it’s not ideal.
@ktsi and @kjj1978, if you’re able and inclined to try, I would suggest you reset your bulbs and pair them again very close to your hub to see if you get a better join. Then see if the Raw Description gets populated and the generic device handler works. You can always fall back to this code again,