Terrain glitch in Larzac, Europa fails defense mission

[Polychroma]

When playing an arbitration defense mission at Larzac, Europa - you will often fail due to a terrain glitch.

Once the infested are mostly cleared, a couple would usually remain buried under a snowy hill at one side of the map. While running around to attempt and lure them out the Arbitration defense NPC objective will usually wander off and manage to fall off the terrain at some point, triggering a mission loss.

Screenshot shows me standing on the aforementioned hill with the map open for positioning.