One of the two units I got had the same “stuck on” problem you described. The cool white LEDs are just always on at max brightness, but everything else seems to work. Feels like a soldering connection issue.
Emailed Gearbest, sure enough they asked for every piece of information imaginable, including a video. Sent them all that and got a refund (already have a couple more on their way; I think this is a fairly rare issue).
I’d like to take this defective one apart to look at it, but that seems like a difficult task!