Stuttering issue when custom skin is used for add-on plane (root-cause and how to fix it)

Sorry, but I set the setting for Generic Model like you said…still problems with stuttering…?!
Personally I have a lot of add-on aircrafts…I get only stuttering in FBW A32X, CRJ500/700 and Carenado PA28, all others without problems…incl. repaints