Brown patches appearing on cream paint

Got the house painted professionally a year + ago and in the last few months have noticed brown patches appearing through the cream gloss paint on our doors upstairs and downstairs. They were perfect when painted. Anyone any idea what this is and do I need to chase the original painter to fix it. He used paint that he mixed himself adding a brown oil from a bottle to the tub of white paint - maybe this isn't the best thing to do? Or is it something to do with the doors - they're not great quality. Thanks.

It could be resin from live knots bleeding through the paint. All knots (particularly in knotty pine) need to be treated with shellac knotting, this prevents the problem you describe.

Thanks Carpenter, does that mean it'll keep happening even if we repaint? Can the knots be treated after they've been painted? Note, its not happening on the skirting which is painted same colour so that would back up your suggestion.

I think you would need to sand back the affected areas to the bare wood, treat with knotting solution, spot prime and undercoat before finishing off the entire door with a top coat.

Ugh sounds like a messy and tedious job - didn't want to let another workman near the house for years. I suppose I should call the painter since he should have done this properly initially - we certainly paid him top price for the job although I supect he'll promise to come look at it, make lots of appointments and never turn up hoping I'll give up and go away - he was a bit like that when we dealt with him before.

ive noticed the same thing in my house, which is only two years old, would i have any come back with the builders obviously the job wasnt done properly