Assure + Ugin's Conjurant still = -2 / -2 ?

Magic: The Gathering - Puzzle Quest MtGPQ Bugs & Technical Issues
1

I cast Assure on Ugin’s Conjurant to try to prevent the -2 / -2 from happening to Ugin’s Conjurant, and it did not work. Just asking if that is working as intended?

Thanks!

2

Update: I cast Sentinel’s Mark on Ugin’s Conjurant and when he blocked an attack he did lose Prevent Damage but did not get -2 / -2.

3

Clarification: Ugin’s Conjurant loses the icon indicating Prevent Damage, but does not actually take any damage.