So I'm running Exchange 2013 CU2v2 alongside Exchange 2010 SP3 (both on top of 2008 R2 SP1) and I'm having a bit of a weird thing happen when migrating test users from Exchange 2010 to 2013.
After migrating a user from a database on the 2010 server to a database on the 2013 server, when you access OWA (through a url pointing at the 2013 server), it still appears to render on the 2010 CAS (and functions normally). If you click ? > About it shows properly that the mailbox server is the 2013 server, but the host address and client access server are still the old 2010 server. It seems that after a few hours it fixes itself. ECP, however, renders properly on the 2013 server immediately after migration. The migration completes successfully with no errors, and outlook connects fine after migration, hitting the 2013 CAS.
I thought maybe this had to do with the Exchange Information Systems Cache, as in 2010 this was occasionally an issue:
http://www.terminal.com/blog/bid/70313/Moving-Mailboxes-During-an-Exchange-Migration
but the mailbox will still render on the 2010 CAS even after restarting the ExchangeIS service.
I should also note that this behavior DID NOT occur with Exchange 2013 CU1 alongside 2010, and only started happening after upgrading to CU2v2.
Does anyone have any thoughts as to why this is happening and what I can do to make it transition quickly to render OWA against the new mailbox? Thanks!