When using the spartan ui and I approach the pool of mixed monstrosities in Maldraxxus, the colored ooze window doesn't pop up. If I disable the addon it pops up.

Hey,
if you mean you can´t see the color count for the rares on the nameplate of the pool of monstrosities, than you just need to go to
Modules > Nameplates > Indicators > Auras
there you will find "Show only Auras created by player"
turn this OFF. (untick it)
Now do a /reload and you should be able to see the color count on the pools nameplate.