I’ve been having this issue this week too.
In my session its related to a material instance of the Custom Creative landscape and adding it to custom meshes. It also might be related to their use with data layers. This is a consistent repeating bug. I rolled back to leave this bug behind but it came back on the same assets when messing with data layers.
Also note this asset was created with modeling mode and not an import.
Before this update these static mesh assets were stable for 4 months.
