I see. I’m sorry as I’m no expert on this, I had that problem once and I fixed it by starting from the empty level, instead of the default one, then adding the lights, step by step, until I realized the problem was the auto exposure.
You may try starting from an empty level and do the same. Make sure you go step by step, testing your Play at every step to realize where the problem is.
I’m afraid I cannot help you further on this, hope you good luck on finding the cause of the overlit level. Maybe someone else will notice what is going on.