Liebherr’s glass-door wine cabinets (the HWgb series) use UV-protective glass specifically because light exposure degrades wine over time — the glass lets you display a collection while still shielding it from the light that would otherwise be a real risk to bottles stored in view. That protection depends on the glass and its seal being intact, so a cabinet that’s been damaged, or a persistent door-seal issue, is worth having checked with that in mind, not just for temperature reasons.
If you’re noticing label fading or other signs of light exposure despite the UV glass, that’s worth mentioning during a service visit even if it’s not the primary reason for the call.