I use the Tamiya paint and TS-13 and never had an issue that looked like that. My process is to wash the body in dish detergent and dry, paint the body with light coats allowing it to flash 20 between coats. When I spray the TS-13 I do the same as when I sprayed the paint except I give it one final wet coat at the end. Have to be careful as there is a fine line between wet and running.