3:58 PM
@des54321 Do you have anything that measures voltages?
If you do, check any random outlet immediately.
Have you had things like toasters cook slower or faster than expected?
It could just be a wonky LED bulb or some wiring that inconsistently connects (which would also be a problem, and potential fire hazard), but my initial thought when I hear "some lights way too dim and some too bright" (although in this case, the same light) is a lost hot leg or neutral.
There's three wires that go into a house/apartment in the US: two hot and one neutral. The two hots are 180° out of phase, and connecting them gives 240v for things like air conditioners. Both hots are 120v to the neutral, and are used for outlets, lighting, and most other stuff. If you lose one of the hots going into the building, half of the circuits in the house won't work, but then once an oven, air conditioner, or other 240v load is on, they'll start working again at lower power.
It sounds like it's just this light though, so you could potentially have that at a smaller scale.
E.g., the neutral or one hot going to a single circuit is either broken or intermittently disconnects, which can cause all sorts of fun stuff like this.
@des54321 That wouldn't be to code either, so I wouldn't expect one to be
What could be happening is that you have something called an MWBC (multi-wire branch circuit), and the neutral has broken. That creates a sort of mini-lost-neutral scenario, where the voltages will fluctuate wildly on that circuit depending on what's using power on it (so maybe the power outage knocked out something else that was on the circuit, and now this LED's getting a bigger chunk of the voltage)
IIRC every apartment is required to have its own breaker panel...oh wait just saw your message that it's not controlled by any of the breakers you have. Odd that there's only four, and odder that none control it. So now I'm even more confused.