Just a thought, but perhaps some of the LED bulbs are burned out or otherwise damaged?
Put them both on FULL ON for all 3 color channels. Make sure they are both oriented the same. And look through a filter, say, some dark glass like a welder's glass(maybe not that dark). They do get bright.
I'd say save yourself time. Take yours to the store and check then IN STORE. Keep the good one, return the not so good one.
I had a similar issue but with speakers. I ended getting a pair of the "last year's model" and I wasn't totally pleased with them,, but when I compared them A/B to the current model, I was much happier with the sound of the older model, the newer cross-over sucked. Same amps, same head end and same cables.