Ah! Testor's isn't water based acrylic. It's an oil enamel, which will dissolve in laquer and acetone. (At least the micro bottles of model airplane paint that they make are.) As whip said, if you want to use the Testor's, you have to seal it with a couple coats of water based polyurethane finish before dipping in the gasket laquer.
Or, just use the Apple Barrel (or equivalent) brand of acrylic paints like you find in craft stores or Wally Worlds. They come in plastic bottles that are about the size of a spice jar and cost a buck to two. Those are water based acrylic and won't dissolve.
Also, even though the acrylic paint seems dry after 5 minutes, let it dry 24 hours before you dip. Another tip is to dip the bare shafts twice in gasket laquer and then crest. The gasket laquer will provide a smoother surface for cresting than the raw wood, and will let you produce cleaner lines. Then make subsuequent dips right over your crest.
Here are some arrows I just made in recent weeks using alcohol dyes for the cap and crown, acrylic paints for the crest, and gasket laquer for the finish. The dye bled a little in the dip tube, but not enough to affect the finish.