@Nosmo
I don’t know about Unity but with UE4 I know that you can’t have more than 4 overlapping stationary lights if they have static shadowing because the lights will be assigned to 4 different channels of a shadowmap texture (RGBA), which is all there is to use. I am 99.9% certain it’s the same for Unity, though I’m very new to Unity so I’ve never tested it. If you try switching the lights from baked or mixed to realtime, that should do it! If you don’t want to use realtime lights there is surely a good solution to it but I don’t got the answer for that unfortunately! Google it!