The purple in meths is a sort of colour dye to prevent it from being drank.
We used to use it many many moons ago until like you… we stained a vehicles paintwork on a hot sunny day.
One of our lads poured some on a bonnet and started to wipe it down. I think the sun beating down had maybe opened the pores of the paintwork or maybe just made it more receptive to the dye, but whatever had happened. it would not budge!
Luckily for us, our customer was also a friend and settled for us covering the area with a large graphic. however, lesson learned and we stopped using it and moved to "industrial meths" which is the same thing without the purple dye, it also comes in 25litre drums and saved us a small fortune on the domestic grade purple stuff.
I never experienced this on a wrap, because back then wraps were not available. however, I would guess its maybe a similar situation that the surface of the wrap film has been receptive to the dye and stained it.
Like us, its a lesson learned!
What I would add is, it’s probably a good lesson because the purple stuff really shouldn’t be used for wraps. as much as it flashes off drying fast, it actually leaves microscopic residue in recesses and the like which in turn promotes possible failures of the wrapping film popping back out of the recesses.
If you do manage to get it back off, please leave a reply here as I would like to know myself if it is possible.