3S Oil pump breakages

I have heard from more than one place now that 3S oil pumps are prone to destroy them self at 8500RPM and over. One guy told me that the drag gets so high that the middle gets torn out of the sintered metal drive pulley.
 
Now I have had taken a pump apart and had a look at how they work and duct the oil, I have to say I think it's a terrible design. Unfortunately even with all with freedom of a 5 axis CNC mill there isn't a practical way to redesign it, there just isn't enough room there to make a better concept.
 
I would like to hear if anyone has had a failure and if they know what broke on it.