Hi, has this been fixed in a recent UE4 version? I’m still on 4.7.6 and have this issue. The warnings only appear with Instanced Static Meshes that have a Static Mesh set that has multiple collision parts. I didn’t count, but I’d say anything above 30 instances added to that ISM cause this. Collisions indeed don’t work when the warnings occur. As soon as I remove all but 1 collision parts from the Static Mesh that the ISM uses, the warnings (and collision problem) is gone.
My workaround would be to create separate ISMs for collision with one collision part per ISM, but that’s really ugly.