At line https://github.com/BluSunrize/TravellersGear/blob/master/src/main/java/travellersgear/client/gui/GuiTravellersInv.java#L213 you immediately reset the Y draw for potions effects to 0, meaning that the actual position of the potions effect element doesnt matter.

True. I'll see to that whenever I actually work on TG again.