So far this has happened twice and UE4 has not submitted a bug report that I know of. I have been working on an Unreal Engine Udemy course and while working on the project that the instructor is working on, the engine crashed in two unrelated circumstances. The first was when I was editing Geometry, first I noticed that the engine was taking several seconds to undo a mistake. After a while, I opened undo history and tried to go back to a point and that was when it crashed. The second time was when I was testing adding my name to a scoreboard so it would be saved. After I entered my name and hit enter the engine crashed with the same behavior.
After the second time, I noticed that my CPU, C drive and all 16gb of my ram was being used up. The engine was using up so much memory that Windows made C drive into virtual memory and started using that once my dedicated ram was full. I notice that the remaining storage on my SSD (C:) was used up with was about 30gb. After using ~36gb of ram and no more could be used, my desktop went black on both of my monitors and all opened applications crashed. Then my PC shut down.