Since we're still unsure about the procrates, my Wind team is super crappy (for T4), so it takes a long time to beat Thunder quests. So I had 1+3 Vine's every time, and no Mordred.
I had 10/12 successes, one resist was after Sphinx resist, one was when Sphinx was up.
The success rate of Vine seems really good for an Eidolon debuff.