I've stripped two repainted frames in the past couple of months. I would try a very light layer of stripper in one small area at a time. Don't let it sit for 15-20min like normal, but give it just 1-2min and wipe.

While doing mine I noticed that when I wasn't patient enough to wait for the stripper to eat through, I would reveal a mostly untouched bottom layer of paint, and that was with rough, indiscriminate scrubbing with sloppy/excess stripping applied.