Sending Email interaction from a segment

We have been in Nav 5 for a year now.

We create email interactions in segments were we are wanting to send the email in the body of the email and not as an attachment. We know about the check marks that would cause the letter to be an attachement and not inserted on the body of the email.

But, we have this issue, with no apparent reason every so often we have the instance where even when specifically told not to put the letter as an attachemnt, Nav decides to send the letter as an attachment.

Our Nav partner has looked at this and cannot see why this would happened,

But it does, and it is very inconvenient and disconcerning.

Has anyone else seen this behaviour? and if so, has anyone figure out a way to fix it?

Thank you for any guidance,