Sounds like a version of what I described in post 3. Photos would help. The drains are designed to be kept clear, to work, not caulked at the exit. My guess is the drainage was fouling the shiny varnish.It look like there are drains in the frames, en window rubbers. On the outside it looks like the been caulking it, i cut a smal piece open under the drain end after some time i found out i can get whit a ziptie from the outide to the inside to the frame. Is this is normal i cant find any information of this type of window frame’s.