This is indeed an embarassing and serious blow to Ericsson. You can bet your a$$ that AlcaLu, NSN, Huawei, ZTE, etc will all be using this as a PR weapon to beat them with.
The shambles in NZ with Alu RAN platform (or a "faulty" server as attributed) was a PR disaster for their RAN team & caused goodwill & reputational damage. T
The fact that this happened twice in a short space of time in a Tier1 operator/account with a piece of equipment that is critical to 3G/LTE networks rubs salt into the wounds.
If I was a betting man, I would hazard that this was a combination of;
a) Redback Networks. The new server smacks of their tech.
b) A software issue/ bug.
The Ericsson statement, as it stands, is just PR spun nonsense.
It fails to define (in anyway whatsoever) what might have occured.
If I was taking a wild guess I would suggest a replication bug that spread across the active/active nodes and lead to a DB corruption. The ripple was not detected quickly enough or propgated quicker than expected and the failback didn't happen, as originally modelled.
When your dealing with an active network with millions of active users & connections, any fail scenario that involves live data and has a revenue authentication and assurance function is the stuff of nightmares! Believe me!