Multiple Hops for local database delivery

Hello folks!

We have a number of Exchange 2013 servers in our lab. Each server has CAS and Mailbox role and there is only one AD site. We are experiencing slow delivery times when the sender and recipient are on the same mailbox database.  Here is the scenario:

• User1 has their mailbox on database1 on server1
• User1 logs in to OWA on Server1 and sends a message to themself
• Wait 30-60 seconds for the message to arrive. Sometimes longer
• Message properties show the message left the local server and went through 4 or 5 other servers before being delivered back to the originating server.

Reviewing Exchange 2013 Message flow seems to indicate that mail will be routed to any server in the mailbox delivery group, but that seems very inefficient if the message sender and recipient are on the same mailbox database.

So my question is:

1. Is this normal behaviour?
2. Any suggestions to prevent the multiple mail hops?

Any thoughts are welcome!

Thanks!

-Fred.