Multiple approval requests for a single email sent - Exchange Online Email Moderation

Hi there,

It's my first post in the community so I'd like to say hello to everyone! 

In our company, we have enabled the Moderation services which means that, if a certain user send an email to someone outside the organisation, a moderator receives a copy of the email or conversation and can then reject or accept it so the message is then sent to the recipient. 

It works fine if it comes to receiving the approval message but anytime you approve any message the same approval email for the same email comes back immediately - you can do it as many times as you want and the approval message comes back anyway. However, the message is sent after the first approval request. Is there anything to do to stop this messages coming back? We have hundreds of messages approved every day and this thing is just very annoying. Please help!

Thanks in advance

Tom