If a new hit is done before the first hit finishes processing, DDD won't end up using the right combat context, or it will update the combat context being used which will affect the old hit that didn't finish processing. A simple stack of combat contexts that get popped once done processing should remedy this. Will need a stack for combat results as well.

This is likely unnecessary the vast majority of the time, so it's not worth adding. A lot of workarounds can be done by using CraftTweaker events