I was running tests today, after noticing the spellement tiers changed for various Ice spells.
Testing Celestial intervention, I noticed only 1 shield was being sacrificed, though it says (Max 3).
I had 6 of them, and still only one shield was removed, resulting in about 700 (boosted with Radical) and about 500 non boosted. Either it's intended to remove one, and the card tooltip not changed, OR it's an bug that it's only taking one instead of the 3 listed.