MVPs being immune to SG

[Yookie]

So some MVPs (regular spawn only) somehow manage to be immune to Storm Gust and only Storm Gust. MVPs like Moonie, Gloom or Skoll who have no business to be immune, really.
This seems to have gotten worse with higher server uptime according to someone I talked to and verified this with.
When checking this I was able to hit the slaves just fine so no LP shenanigans either and other area spells like LoV also worked.
Would be real nice if this could be looked into. Thanks <3