Same Bug in 4.17 and 4.18 i notice that because my SSD of 1Tb have 600Gb of this files inside of DerivedDataCache.
I use RuntimeMeshComponentPlugin of Spine 2d software (Similar to Procedural Mesh Component)
Files are generated at runtime for me in the map where i use RuntimeMeshComponent.
This Problem can potentially Kill Hdd or SSD for the amount of Write/Read operations.
I’ve tried to pinpoint where ProceduralMeshComponent goes wrong. It seems this is an inherent issue with how collision meshes are generated and can’t be fixed. It would be great if someone from Epic could chime in here. All we can do is disable this and have users of our Spine UE4 runtime manually create collision shapes.