I’ve found out i didnt used i had a Typo:
// ---------------------Wrong one --------------------------------------
UPROPERTY(EditDefaultsOnly, Category=Projectile)
TSubclassOf<class Projectile> ProjectileClass;
// ---------------------Good one --------------------------------------
UPROPERTY(EditAnywhere, Category = Projectile)
TSubclassOf<class AProjectile> ProjectileClass;
Look at the name of class,
(names are different then before, rolled back in previous version)