Well they obviously did roll back. But they spent a fair bit of time isolating the cause, then processing all the roll-backs.
All implementation plans have roll-backs but in a large corporate any nightly change window may contain changes for 1-25 projects/BAU maintenance some of which are incremental on top of each other.
A roll-back is not as simple as clicking "undo", and in the case of network ones the changes are pushed out and need to propagate over individual elements - which was problematic if the bad config was preventing them from connecting to said components. Rumour has it staff could not even VPN in.
Someone will lose their job over this one.