We have a 2014 Citadel with the HID lights that had both headlight assemblies replaced due to constant moisture causing the bulbs to prematurely burn out. Driver's side went out at two years and was replaced under the standard warranty. The passenger's side went out just outside the three year warranty expiration and was replaced under the MaxCare Lifetime warranty ($100 deductible). There wasn't any fix for it from the dealer, just straight replacement of the whole light fixture - expensive, but warranty covered it both times.
NOTE: If you have the HID light assembly replaced, make sure your dealer knows how to calibrate the lights so the automatic leveling works again. We encountered one dealer who (claimed they) knew nothing about this and had our headlights aimed at the ground and were shining no further than 10 feet in front of the vehicle. They tried to say the headlight units were replaced to spec and there was nothing they could do about it. Being a major safety issue when driving at night, we contacted the manufacture's customer service directly and they got us in touch with another nearby dealer that could fix the issue. The second dealer knew exactly what was needed and fixed it in under 10 minutes (basically hooking it up to a diagnostic tool to initialize and calibrate the new unit so the auto leveling would work again).
In addition to the headlights, the portion of the taillight that goes across the tailgate is also collecting water now (at 4.5 years) and has had a few bulbs burn out in the lower right side. We are having it replaced under the MaxCare Lifetime warranty (another $100 deductible). Again, no fix for that, they are just replacing the entire assembly.
We didn't have a problem getting any of these lights covered due to moisture/water, the manufacture and both dealers knew about the issue and it went straight to warranty each time.