Maybe too hot... Was it steaming? I usually get my dye to the point that it starts to steam and then turn it off. It may be that the vinyl was not applied well enough. did you run over the vinyl with a credit card before putting the disc in the dye?
yes i use a hard squeegee, i thought it was gonna be my best dye job yet, and yes it was steaming and i kept the heat on but turned it down, i left the dye out overnight uncovered and i worried that would weaken it ,someone suggested i boil it and add a lil dish soap and shake it alot and then put it back on the heat and put the disc in .