The REDL accident was due to the failure or a 2nd stage epicyclic planet gear, not a "critical mast bearing". The gear broke up and one piece was dragged between the epi case/ring gear and the remaining gears which burst the case. Case failure caused the rotor torque to be transmitted through the lift struts which then failed.
And what, if anything, was done to reduce the chances of this happening again?
Perhaps this has happened again.
If it has.
Regardless of statistical evidence of reliability, having a rotor system depart the airframe "every so often" is going to prove unacceptable, to many.