Working on XMS project for a customer which is using KCD for CBA we had an issue with KCD after upgrading the NetScaler Firmware to latest version.
In fact, after binding the AAA vServer containing KCD account to an ActiveSync LB vServer, every time a request was made on the AS LB, the NetScaler crash and the session was kicked.
I was said by Citrix support that this was a bug: BUG684691 and that it should be solved with next release.
The solution was to downgrade the NetScaler Firmware to 11.1 Build 54.14.
Note: Those information are provided based on my own experience.