Split-Brain is not something that can be patched as it is a reaction to a network convergence or change, it is something that could happen with any major network change but does not happen so frequently. Alerting has been added to the firewall to alert us in the event that the firewalls are in a split-brain scenario. This has been added to the existing email alerts for unauthorised access.
Had this alerting been in place before we would have been aware of the split-brain during the border router change window and before the start of working hours.