Signatures Sending Twice

Hi All, 

We are using Office 365 and Exchange Online so I hope this is the correct section as it only lets you select Exchange Server. 

I am in the process of setting up global signatures, while the signature appears fine, when sending to an internal user, it sends the signature twice. but only to internal users. I think I might have the wrong setting somewhere, below shows my current settings. 

*Apply this rule if... The sender is*  (This is selected as I do not want everyone to use this signature yet.) 

and for the time being, I have had to add the rule only apply if the user is "outside the organization" I would ideally like to remove this, but I can't do that while the signature is being sent twice. 

Anyone have any ideas why this is happening? 

Thanks