Warning with Bhashiva's first Khorne event.
So very early on as part of Bhashiva's campaign you get a big lore pop up about fighting chaos and a quest mission to fight Khorne.
You have to go to a specific location within 4 or 5 turns to spawn a khorne army and you kill it to complete the mission and recieve a follow up mission (I assume the collect 4 relics is the follow up).
But the thing is unlike many similar events where you go to a location and a battle immediately starts, you don't actually go straight into this fight. The Khorne army spwans a short distance away, next to the nearby settlement which you'll have conquered by this point most of the time.
But if you don't have the movement range to reach the army after triggering spawning them (like I did) they'll just run off, preventing you from doing the mission and recieving the follow up missions.
For me they actually ran off, took a neaby settlement (probably settled some ruins) went to war with Grimgor, almost died to Grimgor, then the army was barely alive and within range for me to finish, getting the quest completion.
If the AI had wiped them out it's possible the quest would've failed, which could've locked me out the whole quest chain or other parts of the campaign (I can't be sure yet because the DLC is brand new).
At best it's an annoying inconveinece at worst it might lock you out of campaign mechanics, events or rewards.
TLDR: Khorne event army doesn't spawn at specified marker. If you don't have the movement range to reach it on the same turn it runs off delaying completion of quest line. Also potentially causes other issues. Might even break quest chain or other things (can't confirm yet).