Outlook Voice Access - Pause After Entering Extension

I’m wondering if any of you have noticed the behavior detailed below.  Just wanted to see if this is something unique to us.  We’re running Exchange 2013 CU10.  Four servers running in a DAG and all servers running mailbox + CAS roles…

When user mailbox is in database active on same server as database hosting system mailbox:

1. User dials UM pilot number (Outlook Voice Access)
2. UM picks up without delay and prompts user for extension
3. User enters extension and presses #
4. User receives prompt for PIN without delay
5. User enters PIN and is immediately placed into mailbox

When user mailbox is in database active on different server than database hosting system mailbox:

1. User dials UM pilot number (Outlook Voice Access)
2. UM picks up without delay and prompts user for extension
3. User enters extension and presses #
4. User hears 4 rings
5. User receives prompt for PIN
6. User enters PIN and is placed into mailbox without further delay

So…has anyone else noticed the extra rings between entering your extension and being prompted for a PIN in the situations describe above?  Thanks in advance for any feedback.