Bad surface conditions. Further layers do not stick on the first layer. First coating is not yet completely dried. Extend drying time, remove loose particles and coat again. Exfoliation and cracking.
Coating is too thick.
Dilute coating in such way that thinner layers can be applied. Cloudy, uneven application when spraying. Coating is not stirred up, spray gun is led jerkily not homogenious. Stirr coating or use mixer. Pull even courses with spray gun.