Since posting this I’ve tried:
- Remaking the landscape from scratch in a new project out of a new batch of heightmap files
- Migrating the old map to a new clean project
- Cutting the landscape up into 4 smaller chunks and stitching 4 separate landscapes together
- Lowering the collision mip level
- Setting a lower collision mip level for the simple collision
- Forcing the map to LOD 0, forcing it to LOD 1, and forcing it to LOD 2
- Disabling texture streaming
- Changing the world partition grid sizes to match the landscape component shape
- Shrinking the world partition distance to only render a tiny area at once
- Increasing the world partition distance to render a huge area at once
- Removing foliage and all actors except the landscape itself, the player start, a directional light, a sky light, and a sky atmosphere
It will sometimes take an hour or more for a landscape component to fail, but it inevitably does fail. I’ve been doing some GPU and CPU profiling while this is happening and both never approach capacity, VRAM has never approached capacity, and system ram usage is pretty low. No issues with streaming pool sizes or anything similar.
Also maddeningly, this only happens in the packaged build. No matter how much I test, it never fails once in editor. I’m a little at a loss after weeks of trying to debug this.