Greenveg, I certainly do think it matters, but for this specific LED keychain linked seems to be working. Maybe that's the issue, Eastern has certainly tried this with MR boards and that particular keychain. So I agree, if you know a similar product you have that has PWM and it acting weirdly, the PWM is probably causing it.
Luminara, the input is probably out of the puck's range for what it wants to see. That's why initial I said a power extender or relay.