Stumped on this one. I understand why a change of email or subject line will cause an email reply to an opportunity to show up as a new opportunity, but we have several that are doing this when all the info is the same. The only patterns I've noticed:

• Every time this happens, the customer's email client ads "Re:" to the email subject. But it does not keep adding "Re:" with each reply. For example, each of these would be a new opportunity: "Looking to order" "Re: Looking to Order" "Re: Looking to order"

• Each time a new opportunity is created, the assigned sales team changes. The original opportunity was manually assigned to "International Sales" but each succeeding opportunity is "Direct Sales", "International Sales", "Direct Sales", "International Sales", etc.

Any suggestions? We just realized we've lost a fair amount of business to this glitch, so I want to resolve it as soon as I can. Running v9.0c.