Naxx: Anub'Rhekan's Locust Swarm applies dot stacks before the cast has finished.

[SuzumiK]

In the level 60 version of Naxxramas, Anub'Rhekan's Locust Swarm applies dot stacks before the cast has finished. This makes it really hard to avoid the damage.
In the level 80 version, the dot only starts stacking once the cast has finished.

[ZhengPeiRu21]

Thank you for reporting this issue. I will look into it.