We have changed our company MX records to point our emails from a MS Exchange server to Google Apps for business. This was done 2 weeks ago, so the MX records should have propagated, which intodns and mxtoolbox confirm.
Since then, around 95% of all emails are being sent to our GMail accounts, and the rest to the old exchange record. Because of this, we have set up both accounts on Microsoft Outlook to ensure that we don't miss out on Client emails.
Could this be an issue with Outlook? When I deleted my old Exchange account from Outlook, I no longer have this problem other than from internal emails from my other colleagues who are using Outlook. But my colleagues using Outlook have trouble receiving emails from clients.
I have tried a DNS Flush on the outlook machines, but that has not fixed the issue.