I'll never use any kind of 'disappearing' pen again. When I first started quilting, about 30 years ago, I used such a purple pen (don't know the brand anymore), although my mother warned me. No problem in the first years, but I guess it was about 15 years later that it became obvious that over time the invisible residu had literally eaten away the fabric.
I only use tape, chalk, soap slivers or sometimes an aquarel pencil of a good brand like Faber-Castell. No magically disappearing stuff anymore.