Caulk or silicon on skirtings ruining wall paint

I’ve recently decorated the house. I think our painter used caulk or silicon around window sills and on top of skirting boards.
For some reason there seems to be some discolouration of the Matt wall paint and I’m wondering what the cause could be?
I did try painting on top a very light coat but it doesn’t seem to cover it.

Please see pictures below.
Is there any advice in what I can do? It’s not everywhere just some areas and it’s not hugely noticeable.