Arbitrations Defense Target falling off the map (Mission Failed)

[SlyFoxForgotten]

Arbitration defense target fell through the map after wave 15 cleared, causing a mission fail. Lost 12 Vitus 😔

Exactly as this old post from 2017 

My guess is a recent patch broke the fix, as OP says it happens specifically on a snowy bank/hill part of the map.

Reproduction would be through RNG, as only the AI can dictate if this happens, and when the round ends (I presume)
This was with a squad of 4, we were breezing through it and decided to go till 20, Causing the mission fail, lost everything but the round 5,10,15 items.