I am wearing miraaks robes and when i summon my creatures sometimes when i summon them?

Absorb has allways worked that way since release. Any spell cast at ya (by your enemies or yourself) have a % of being absorbed, That includes summons.

Yep. Spell absorption has always worked this way; if you play a conjurer, you're screwed. Be glad that it's only 15% and not 50% from the Atronach Stone

Its a known bug, summons count as an on self casting, and don't count as beneficial.