Anyone have issues with the Isilon not communicating after a Switch Upgrade?

This weekend we tried to to an upgrade to the Extreme 460 switch connected to our Isilon.  The upgrade seemed to go well and everything other than the Isilon connections came back up.  From the Isilon we couldn't ping from one node to the next through the switch.  The network guys said that they had seen this before and the Isilon needed to be rebooted.  After the reboot of the Isilon it did begin communicating with and through the switch.  Now while this worked it does seems suspect as we have rebooted the switches on the Isilon before without issue.  So has anyone else seen this issue or something we needed to do with the Isilon to prevent this issue?  We would just like to understand what happened and why so we know for the future.