Hi, I'm using the "Long Buff" and "Short Buff" groups. I'm noticing that Horn of Winter is always showing up in the "Long" group, even though the duration is less than 2 mins. Is that intended? I was under the impression that anything under 2 mins should be in the short buff group.

Horn of Winter lasts exactly 2 minutes, so it sits right on the boundary between long and short buffs. However, buffs are considered long when they are at least 2 minutes, so Horn of Winter falls into that category (barely).