It won't recognize if you set Dex to raise and another stat to lower, instead it continues to insist that you 'cannot gain from this potion' and won't let you drink it.
You need to have an unassigned point in order to drink the Essence which makes them completely useless for people who already reached their overall stat cap, when most of the people who find them are already at said cap.
I have not tested the Strength and Intelligence essences yet (and can't test the Strength one because I'm at the highest allowed cap) but I would imagine they're affected the same way.
Edit:
Now I'm really confused, haha.
I had my Intelligence reduced so that I could continue raising my Dexterity and I still can't drink the Essence of Dexterity.
In this case I have no clue what the issue is, I am below my stat cap and therefore have free points to assign so by all means I should be able to drink the Essence and gain.
Guess it's back to the training room without any gear on for a few days solid
