If you look at it close it looks like the original white paint stripe. They may have built up the sides with primer instead of sanding all the old paint off to get a smooth surface going. Is yellow the color of the car's resin structure?
Yes, that yellow-ish color in between the cracks does indeed seem to resemble resin, it looks so fresh to me that I severely doubt that it could be bondo or primer (which I think usually has a different color). It looks exactly like the color of the small resin bits I sometimes use in my scale model plane hobby, which look equally bright and fresh to me. This makes me wonder if the entire roof panel got replaced at a point in the car's history, very indicative of this would be the abnormal ding and raw panel edges in the 5th picture. It would also explain that it does not occur on any other area on your car. Apart from that I have razor sharp eyes that enable me to spot these things kinda easily
I think I see several layers of paint shifting both together and separately, due to poor quality paint/additives and a paint guy being in a rush.
1, stripes on top of a totally unprepared (as in bondo, primer or anything) raw resin top.
2, blue coat at least partially sprayed (heaven forbid rolled
) on top of this and then left to cure (visible in one area yet not visible in other areas), which can be seen very well in the first and fourth picture at the start of this thread.
3, after being cured everything is sprayed blue entirely this time with white stripes rapidly applied over the still wet blue paint (which would cause them to perfectly shift along with the blue in some pictures).
4, clear coat over all of this to cover up the entire series of mistakes (no paint flakes visible).
Conclusion: everything was fricked up right from the getgo, getting worse along the way.
MIND YOU I do not have experience in car paint, just making a series of well judged conclusions on what is happening here, based on 10 years of experience in building and spray painting scale models