This is exterior paint. The house originally had oil based paint from new, and up until 3 years ago I would always repaint with oil based. I hired a contractor to switch over to latex and everywhere he painted is fine except these 2 areas that also gave me issues for the last 15 years or so. The garage has a flat roof and there is an 8" wood molding that sits just below the roof line. I am pretty sure it is mdf. There are 2 spots that the paint just starts to peel off forcing me to repaint these areas every 2 or 3 years... Everywhere else on the house that the paint was used is perfect. I am going to scrape it down and sand it once again but wonder why these 2 areas never accept paint for long term? What can I do to remedy this?