It was probably condensation that created the short circuit.
I've seen these type of LED cabinet accent lights in the hardware section of the grocery store.
I wouldn't have mounted those lights there due to the moisture that evaporates & collects in the canopy from in the hood. You know the cutouts from the filtration, heating equipment, tubes & electrical wires.
I had a relatively low end = LED accent light that was inside a CLEAR plastic tube, meant to be used inside of the TANK, but one evening before the lights came on I noticed WATER managed to work it's way INSIDE the SEALED tube.
When I removed the lousy accent light from the tank... the water that made it's way inside was brown & rusty because the ENTIRE circuit board where the LED's were mounted was SOAKED.
After closer inspection, I figured out, the water got in through the cracked plastic wire for the electrical adapter.
I assumed the thing was garbage at this point, so I disassembled it. I cut open the "waterproof" seals with a sharp razor & pulled out the silicone plug.. drained out the rusty water & rinsed the whole circuit board in the sink till the COLD water went from rusty to clear.
Gently dried the LED board & left the whole thing on top of a fan overnight. In the morning, I hung the parts on a coat rack & let it air dry for another 3-5 days. The next time I plugged it in was probably 7 days later & all of the formerly submerged LEDs STILL WORKED!
(I'm not going to bother sealing this thing back again with silicone & replacing the crappy split wire, so it'll be mounted OUTSIDE of the aquarium if I chose to use it again)
Your fixture had a OVERLOAD from HEAT, but it could have also been caused by cheap parts, or most likely a short circuit from moisture which cannot be repaired as easily with replacing the burned out parts or bypassing that DEAD LED.
The amount of time it would take you to repair it if it's EVEN possible, is probably not worth it.