Circle of Balance Druid, Cold Embrace

The Cold Embrace feature states this: Whenever you damage an opponent with a spell, they are unable to heal any HP until the start of your next turn.

My druid just got the feature, and saw it in action. I cast a spell, damaged a few opponents with it, and saw the debuff apply. However, when it came to said opponent's turn, the debuff ran out at the start of its turn, and they used a Second Wind to heal themselves.

It seems like it's simply bugged to run out at the start of the target's next turn, instead of the druid's. Which makes it very unlikely to actually make any difference.