If you repeat at many times, it won’t become true) Look what TheJamsh said about how PhysX is used - “all of the collision code for the entire game”.
Havok sim can freak out as well, but it deals with consequences more gently, I’ll give you that.
Havok bugs examples - http://www.youtube.com/watch?v=h4NdPepMemE (Skyrim), http://www.youtube.com/watch?v=IK4jaNwu_4g (WatchDogs), http://www.youtube.com/watch?v=AVJbdL83UmU (Battlefield), etc
Thats more like it)
And don’t forget to share your effort with the community, so with combined effort physics in UE4 can be further improved)