I was only able to reproduce this issue after receiving the user's project.
The project he provided crashes when I follow his directions, but after looking at the blueprints involved in the crash repro, it seems he is attempting to spawn instanced destructible meshes at runtime.
1. Open the test project and press play (you will need to wait a minute for it to respond on initial PIE)
2. Once in play mode, press the G key.
3. Click and hold the left mouse button and drag the mouse across the screen.
4. Crash occurs after a few seconds.
Head over to the existing Questions & Answers thread and let us know what's up.