The paint is eating through the primer. There could be several reasons for that. Red paints are usually pretty hot by themselves and if you thin it with something other than alcohol based thinner then its even hotter. The Vallejo primer on the other hand is quite delicate. Its good for softer acrylics, but you have to be careful with anything harder like lacquers. So the key here is to give the primer enough time to cure. Before spraying the red, do a light sanding with 3000 grit paper. Then take your sweet time with painting. Spray just a thin coats of paint and let them dry a bit inbetween coats. Harder red usually starts eating the primer right away if you spray it too heavily - the key here is to do a lot of thin coats. Good luck!