Is: Garnag, Dark Adherent broken, or working as intended?

I have come across {{Garnag, Dark Adherent}} a lot lately in the higher-tier (5-1) ladder. It seems that Garnag's ability acts as an "Aura", but when you silence or destroy him, your Magicka stays at 7. All other "Aura" cards I have seen will revert the field back to the original state if they are silenced or destroyed.

I was curious why, after searching for his name in this Subreddit, I did not see anyone else making a note of this. I am sure - given his Legendary status - this [what I consider a] bug could be shrugged off as a technicality, but the fact that your Magicka does not revert back after Garnag is silenced or destroyed has made him [imo] one of the most powerful Legendary cards in the game, bordering on broken.

Call this a rant or just being salty, but I have not personally seen a single other card have such a drastic effect.

Other people's opinions are obviously welcome.