In Exchange 2010 UM SP1 we have changed our platform to UCMA. We are now doing more checks for incoming SIP requests to make sure it is compliant and does not have any undesirable effect. As a result, the invalid end quote is causing the request to be denied by UM. This is a by design feature of SP1. CCM needs to address the issue. First the gateway is adding same diversion header twice, which does not seem necessary. Secondly, diversion header the format for display name is incorrect, it has one extra end quote.

Symptoms

Event Error that is generated on Exchange 2010 UM SP1 server:
Event ID: 1021
The Unified Messagin server rejected an incoming call with the ID 82e08200-c7d109fd-f6246-1602010a@xxx.xxx.xxx.xxx. Reason: "Invalid Route header: mismatched character: expected: "", found: "EOF""

Read the full article here:
http://blogs.technet.com/b/wesglock/archive/2010/09/07/exchange-2010-unified-messaging-sp1-um-rejects-incoming-call.aspx