After a mailbox move from Exchange 2010 to 2013, there seems to be an hour or so delay before ActiveSync starts working again for that mailbox. External and internal DNS is pointing to the Exchange 2013 CAS, which proxies everything just fine for mailboxes still on the Ex2010 server. After a mailbox move from Ex2010 to Ex2013, Outlook and OWA work perfectly fine and get proxied to the proper mailbox by the Ex2013 CAS immediately, but activesync does not for about an hour or so.

Running the ExRCA for Activesync with the credentials of the mailbox that just moved it fails at the Attempting to send the OPTIONS command to the server, with a HTTP 403: forbidden. Interestingly, even though the mailbox is fully on the Ex2013 server, it seems that the Ex2013 CAS is still trying to proxy the activesync session to the Ex2010 mailbox (in the ExRCA error, the X-CalculatedBETarget is still pointing to the Ex2010 server), and since the user is no longer on that mailbox you get the permission error. If you wait an hour or so after the mailbox has moved everything starts working properly and X-CalculatedBETarget points to the proper server when you run the ExRCA. 

So my question is: is it normal for there to be a delay in ActiveSync after moving the mailbox? Is there some kind of cache on the Ex2013 CAS for proxies that just takes a while to time out before it starts proxying activesync to the proper mailbox? is there any way to change this behavior if it is normal? Both Ex2010 and Ex2013 servers are in the same AD site, so there isn't any cross-site AD replication lag, and I'm not seeing any ActiveSync related errors in any of the logs. Thanks!

(Also I should note, the accounts I've tested moving are just normal AD accounts that have the 'Inherit permissions' checked in AD. I'm aware of the issue with privileged AD accounts sometimes not getting the proper Exchange permissions inherited causing ActiveSync to fail, but that is not the case here)