I am no expert but I would agree with some of the others it looks like contamination. On my Olds I painted I had a very similar problem but only in small doses in the door jams where the ruber seals contact the body Armorall was the culprit being used to help soften those old seals. One thing I noticed was it did not occor all the way around but sporadically, I did not sand the jams just cleaned and sprayed aresol parts cleaner on it not sure what is a sure fire way to remove stuff like that and perhaps if I would have been more aggresive the spray but I was trying not to get it everywhere and it dries pretty fast when sprayed on a rag and I only had one partial can on hand to clean 4 doors.