Outlook 2016 Delay Rule for sent messages but can't send early from Outbox

We use Exchange 2010 (On-Premise) and just went from Outlook 2010 to O365. One user has always had his sent emails delayed for 5 minutes.  If he wants to send an email early (after he has sent it) he would open the email in his Outbox and click Send and the email would send early (that was in Outlook 2010).  I set up his rule in the new Outlook O365 and now if he tries to send an email out early from his Outbox the Send button doesn't do anything. If he opens the email click the Options Tab and unchecks Do not deliver before and then clicks Send it still doesn't send the email out.  If in Options he changes the time for the delivery to a time before the current time and clicks Send it will send the email out of his Outbox but it will not be delivered until the original Delay time has been met (5 minutes).  Does anyone know why he can't Send the emails out of his Outbox early by clicking Send in emails inside his Outbox like he did in Outlook 2010? I tried the same setup with my email account and it works the same way with me as it does with him.  I am using Win 7 he is using Win 10 but they both do the same thing with O365 (we both have it).