My editor crashes randomly - logs say !Primitive->Bounds.BoxExtent.ContainsNaN()

I’m developing a big 4x4km openworld RPG. I can’t pinpoint the exact time that testing the game started crashing my editor (or my GPU) - screen goes dark, can still hear PC humming but can’t do anything - have to restart PC.

It happens only after testing the game a few times, or working in the editor for a long time, then testing. I feel like something is building up and then reaches its limit and shuts down. BUT WHAT?? How can I tell from this mumbo jumbo what is causing the crash?

Any help is greatly appreciated :slight_smile:

[2019.10.04-23.38.38:992][292]LogStats: FPlatformStackWalk::StackWalkAndDump - 0.618 s
[2019.10.04-23.38.38:993][292]LogOutputDevice: Error: === Handled ensure: ===
[2019.10.04-23.38.38:993][292]LogOutputDevice: Error:
[2019.10.04-23.38.38:993][292]LogOutputDevice: Error: Ensure condition failed: !Primitive->Bounds.BoxExtent.ContainsNaN() && !Primitive->Bounds.Origin.ContainsNaN() && !FMath::IsNaN(Primitive->Bounds.SphereRadius) && FMath::IsFinite(Primitive->Bounds.SphereRadius) [File:D:\Build++UE4\Sync\Engine\Source\Runtime\Renderer\Private\RendererScene.cpp] [Line: 1187]
[2019.10.04-23.38.38:993][292]LogOutputDevice: Error: Nans found on Bounds for Primitive LandscapeSplinesComponent_0: Origin X=-nan(ind) Y=-nan(ind) Z=-nan(ind), BoxExtent X=nan Y=nan Z=nan, SphereRadius nan

I should add I have no Landscape Splines Components which makes the message even more confusing.