Yeah I didn't mean that they mishandled it in the sense that they screwed up, but that they carried out some incorrect actions due to deficiencies in the information they had at the time.
These days I would imagine you would have to be very unlucky to have a bad rollback encounter, most if not all the engines are modded and the procedures for dealing with are well known to crews (including in the sim).
From the report (VH-JJP incident):
The possibility of engine roll-back during high altitude cruise in high ambient temperatures, with engine and airframe anti-ice on, was addressed by the aircraft manufacturer in several Notices to Aircrew prior to the VH-JJP occurrence.
Significant factors
1. During high altitude cruise, the aircraft encountered a pool of moist air which was significantly warmer than the surrounding air.
2. The selection of engine and airframe anti-ice by the crew placed a bleed air demand at, or slightly above, the maximum on the four engines, causing them to ‘roll back’.
3. An Operational Notice published by the aircraft manufacturer did not provide information of sufficient clarity to enable the crew to recognise and deal with the ‘roll-back’.
4. Engine core icing probably prevented the recovery from the ‘roll-back’ until the aircraft descended below the freezing level.