Yes, that's true. The thing is, activating eternal essence automatically reverts the game to version 3.0, and since the mod itself is designed for version 3.1, it causes a lot of glitches.
If you want to play with eternal essence without glitches, the best solution is to install the eternal essence mod on version 3.0 of the game.
But is it possible to install EWA on 3.0, and what's the point of adding EE to EWA if it causes massive slowdowns?