I think that it can be caused by too fresh paint.Do you use acrylic paints or oil (Humbrol),'cos I dont remember that ones you prefer?And what is the period of time between painting colours and removing the tape?
I think 4 houres aren't enough.I usually remove the tape the next day.The paint must be dry.But if you could upload the pic it could help much.Do you use a primer for the acrylic colours?
BTW Do you have something for your siggy,I'm waiting for this.
I get that all the time Adler. When you spray, keep a good distance from your model and make sure the tape is applied REALLY tightly on the edges, but the biggest thing is keeping your distance.
I havent run into any problems.... Everything seems to be working fine now.... I tightened the fittings on my brush and the vapor problem went away... Ill post some pics tonight...