Kana's Turban's +1 Intellect Suppresses Drinking Horn of Moderation's +2 Intellect

[Alweth 102]

When equipped, Kana's Turban's +1 Intellect suppresses Drinking Horn of Moderation's +2 Intellect. As I understand things, this is the opposite of how it should work. If you have the drinking horn equipped, unequipping Kana's Turban increases your intellect by 1.

[Loren Tyr 555]

Generally speaking it should work in the opposite direction, yes. Highest bonus should prevail. But the Horn is the one with the "only when > 50% Endurance" +2 Intellect, right? It probably goes wrong because it isn't an unconditional bonus, I suspect the stacking system isn't quite able to deal with that properly.