If foliage has active “Enable Density Scaling” and player changes foliage scalability setting during runtime, the editor and packaged game will crash.
Steps to reproduce:
1: Create a blank project in 4.18.0
3: Create a foliage in scene using any static mesh
4: Select foliage type static mesh and set “Enable Density Scaling”
5: Run game
6: Press Shift+F1 to get control of mouse cursor during play mode
7: Open Settings → Engine Scalability Settings → Change Foliage quality to High or lower
Changing foliage quality with blueprints also crashes a packaged project
[Example Project Download][1]
Edit: This is the error message from packaged project by changing foliage settings through blueprints.
Assertion failed: DestInstanceIndex != INDEX_NONE [File:D:\Build++UE4+Release-4.18+Compile\Sync\Engine\Source\Runtime\Engine\Private\InstancedStaticMesh.cpp] [Line: 127]
[Download Crash Dump Attachment][6]