Muyib Spec-op

So with the change to bioimmunity this edition, the Hassassin Muyib Spec-op has become insane. With 5 XP it can get itself up to BTS12 with bioimmunity. This 5 XP spec-op model is now harder to hurt than a tag in cover. Worse still is that there aren't many AP BTS weapons, and many of them are damage 13. Monofilament can't even work.

Some of the best close combat monsters in the game will struggle to hurt him.

This doesn't feel right or appropriate for campaign play, that somebody can instantly have an almost invulnerable model.

I'm not sure where the appropriate place to post this is. It isn't a rules question (outside why bioimmunity is what it is)

We are looking at starting a campaign when lockdown passes, and I am not a big fan of instantly banning a spec-op build out the gate but I cannot figure out how this guy is appropriate for any form of play. Even capping him to BTS 6 creates a pretty crazy spec-op really quickly compared to all of the rest.

Thoughts? was this just an oversight when converting N3 to N4 spec-ops?