Next update

[Banjaa-deathwing]

Well - turns out it’s spell batching:

Spell Batching in Classic

Since we first announced World of Warcraft Classic, we’ve seen questions about spell batching. While we never really eliminated spell batching in WoW, we did change how (and how often) we process batches of actions coming from players, so you’re less likely to notice that processing in today’s game. We’ve been working to ensure that in WoW Classic, the gameplay of activating spells and effects will not differ from the experience of playing original WoW. It was relatively common in the original…