Summary:

In a 7.2i CRM system, open a company and create a new case then save it.
Go to the communications tab for the case and create a New Email from the actions list on the right menu.
Ensure that the email is valid and then send it. Note that the communications tab now shows 2 identical communications.

Symptoms:

Duplicate communications created under a case for new emails.

Resolution:

To resolve this issue upgrade to CRM 7.3.