"My" understanding from afar is that an elastomeric bearing 'retaining' plate disbonded from the blade spar, which is a known isolated problem that does not normally cause any further complications. However in this instance, the bearing then migrated away from the plate.
The same blade was the subject of a 'hangar' incident a short while ago. Perhaps the two are linked?
Apologies in advance to any engineers reading this, I'm sure my terminology is all wrong!