Issues on reflecting proc or skill

[Futumsh]

So does that mean all damage reflection gonna be capped at level 71 after expansion, similar to the %health damage got capped at level 66?

Not exactly capped - a level 71 item providing damage reflection will lose effectiveness against content over 71, a level 74 item against content over 74, etc. Warrior ultimate acts as warrior's level vs content level.

The bug here was that content that should have been considered 71 was being considered higher level, due to higher level scaled mobs.