Have you ever done Titan HM and get entombed in rock? You get a status debuff at the same time that gives a really large determination down. Healing that person with regular heals is almost impossible as it does 60% less healing points cured.

The same debuff is available from fighting Hydra, one of his AoEs gives Determination Down and the only way to give that person a good cure is by using Lustrate which is based on a % of that persons' HP.

I have not seen any information on determination affecting the cures a healer does on someone else.
If it does, please provide link and reference, I'll be happy to read a testing or two to change my mind on this stat.



Unless there's a mistake from SE's part, it might be a huge oversight/mistranslation.