Multiple Token Responses Generated

Hi all

Wondered if anyone has encountered the following. 

We have recently finished the upgrade to Defender 5.8.2 and have started testing E-Mail Defender Tokens. 

Whilst I can successfully authenticate with the e-mail token by using a 4 digit PIN combined with a 6 digit response, as soon as a user successfully authenticates into our remote solution (they can acces the internal resources), they receve a 2nd e-mail containing a 6 digit response which is not required. 

Is this a known issue?

Many Thanks