Voxel related(?) CTD

After good 30 hours playing on a modded game with friends, I've started getting a CTD about 2 minutes after loading the save and it appears to be something related to the voxels. Pretty sure it isn't mod related, and we did build into the side of a mountain (on earth-like) and I feel like that could be related. Hoping there's a fix so we don't have to start over. Here's the exception:

2021-06-10 23:27:25.288 - Thread:   1 ->  Exception occurred: System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
   at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   at Sandbox.Engine.Voxels.MyVoxelGeometry.GetCellLineIntersectionOctree(Nullable`1& result, Line& modelSpaceLine, Nullable`1& minDistanceUntilNow, CellData cachedDataCell, IntersectionFlags flags)
   at Sandbox.Engine.Voxels.MyVoxelGeometry.Intersect(Line& localLine, MyIntersectionResultLineTriangle& result, IntersectionFlags flags)
   at Sandbox.Game.Entities.MyVoxelBase.GetIntersectionWithLine(LineD& worldLine, Nullable`1& t, IntersectionFlags flags)
   at Sandbox.Game.SessionComponents.MySectorWeatherComponent.IsPositionSafe(Vector3D& position)
   at Sandbox.Game.SessionComponents.MySectorWeatherComponent.ApplyParticle()
   at Sandbox.Game.SessionComponents.MySectorWeatherComponent.UpdateAfterSimulation()
   at Sandbox.Game.World.MySession.UpdateComponents()
   at Sandbox.Game.World.MySession.Update(MyTimeSpan updateTime)
   at Sandbox.MySandboxGame.Update()
   at Sandbox.Engine.Platform.Game.UpdateInternal()
   at Sandbox.Engine.Platform.Game.RunSingleFrame()
   at Sandbox.Engine.Platform.FixedLoop.<>c__DisplayClass11_0.<Run>b__0()
   at Sandbox.Engine.Platform.GenericLoop.Run(VoidAction tickCallback)
   at Sandbox.Engine.Platform.Game.RunLoop()
   at Sandbox.MySandboxGame.Run(Boolean customRenderLoop, Action disposeSplashScreen)
   at SpaceEngineers.MyProgram.Main(String[] args)