Arrogance Gem + Vitality + March of the Legion boots

Hi y'all!

I just got a March of the Legion boots with +5 to aura gems.
After equipping the vitality aura gem to it, the arrogance support gem does not work with it anymore.
I tried it on a different equipment with +2 level to gems and it work just fine.
Is it a bug or some kind of restriction?

P.S:

I also tried determination and purity of elements to no avail.

Thank you in advance for any replies.

Arrogance Support: "Supports any non-blessing skill with a reservation."

March of the Legion supports socketed gems with Divine Blessing, making them Blessing skills.

Thank you very much for the reply and explanation.
It makes sense now.
It's a bummer though, I thought that +5 level would give me a boost.

Lifetap also only supports non-blessing skills, so it wouldnt work on March of the Legion boots

Inspiration support.