Could well be the led unit itself, or at least (and more likely imo), the associated driver circuitry included in the pcb of the unit. Personally though, at that price, I’d check for supply wiring faults first, before condemning the led unit. Can you put a voltmeter on the led unit, to ascertain whether the supply might be intermittent, as opposed to the unit itself being intermittent?
I know that on some cars, a weak point is the cluster of flexible wiring that links the car body to the hinged boot or tailgate. The wiring harmess can get chaffed or trapped, leading to damage. If it a simple cluster of wires, you could try gently manipulating it to see if it affects the light?
On other cars I’ve had (an old Astra springs to mind) there was no wiring link at all, just three plungers on the tailgate that made contact with three plates in the lower edge of the frame, above the bumper. Problem there was, unwanted things could get trapped in the contacts, breaking the circuit, or shorting it and blowing fuses.