What's up with AST's Noct shield delay?!

[Leaping]

As an addition I'll just try to describe what I actually see when healing:
- I start casting Aspected Helios [2.95s cast)
- Heals come up on people (health bars rise) [~0.5 sec]
- Shields are applied [~1s total - it seems the shields appear one by one, but that just may be on the HUD only]
- Shields MAY be consumed [~1s to 2s !]

It feels like the game decides if the shields will be consumed right as the enemy starts its attack, but not the animation. Would that be it? If so, mistake, or just intended? :/