I hope it is just a setting, may be I missed.

We have several users receive and email that contains a distribution list in the TO/CC fields and when they click on "Reply to All", sometimes it lists the individual in the DL plus the DL; sometimes it retains the DL without expanding the membership.

The issue is bothersome because they have to remove all the individual email addresses before "reply all" to a DL.

Any idea?