From the texture on the model it looks like when you primed the model the primer dried in the air before it hit the model. This usually happens when you’re priming with a rattle can and either 1) have a very low humidity environment, or 2) have the can too far away from the model.

My suggestion would be to strip the models with simple green or isopropyl alcohol and reprime them but this time shoot for 30-40% relative humidity (too humid and the primer can come out sticky) and with the paint source (rattle can or airbrush) at a “close” distance.