Well, this didn’t take long:
The upper five-LED string in the middle module failed open-circuit, which left the remaining two strings handling too much current. The five LEDs across the middle look like they’re running at War Emergency Power and the lower five are limping along:
The dark spots in the middle are overexposed pixels.
I soldered in a replacement from the same bag and it’s all good again, but I expect that won’t last very long.
The Smell of Molten Projects in the Morning 
Spam comments get trashed, so don’t bother; you’re not as clever as you think. Comment moderation may cause a delay.