flat dormer roof - condensation?

I have a bungalow with a dormer on one side (existing when we moved in a couple of years ago). I've just noticed some water drops on some of the GU10 ceiling light fittings under the flat dormer roof and all the lamps are really warm (switched off). The sun is blazing today and that room is 25C with the windows open a bit.

So I pulled out one of the lamp holders which seemed bit rusty inside, the inside space was very hot/humid but didn't feel wet. From what I can see through the hole the ceiling is plasterboard, possibly a vapour barrier then a thick slab of foam, there then looks to be a bit of a gap between the top of the foam and the external wooden (and felted) roof surface. The plasterboard (under a bit of flaking paint) around this particular lamp is slightly darker colour (damp) but not soggy, and there is evidence of previous owners painting over peeled off paint around this lamp.

I haven't noticed anything when it rains. The lamp holders do have old water drop stains on them so looks like it is a long running issue, but whether it is just a hot weather thing I dont know.

Any thoughts on what might be going on? I'm sure the lights are not airtight so moisture could travel up into the space above the lights, but that room does tend to be fairly well ventilated.

Common problem with heat rising into a cold roof.

The vcl is doing its job, now limit the moisture generated in the house make sure the extractors are up and running and so on