I’ve got the solution from Marco Ghislanzoni (https://www.youtube.com/c/MarcoGhislanzoni)
There is UE4 parameter called Bounce Threshold Velocity which indicates to physx what is the minimum velocity of the object to allow bouncing calculation.
Project Settings → Physics → Simulation → Bounce Threshold Velocity
The default is 200cm/s. In my test the object velocity is 100cm/s, so no bouncing happens.
After changing this parameter to 10m/s, I’ve got bouncing according to Restitution value.
Additional note:
The bouncing results may not always be elastic perfect - this may happens due to the physx solver numerical errors. This can be fixed by adding sub steps.