Partial fix Retail customers not getting order emails

Affected Version
3.1 RC6


retail guest account customers are NOT getting any emails from server, the mail tab is blank!!! no email is sent for order placed confirmation, no email sent when imei order is success or failure? please check and fix this bug, using rc6. Other users are find, just paypal guest orders and retail are affected. I have checked few retail orders and none of these profile show any email log under mail, its blank.