I've got a strange issue with some tickets. E.g. attached screen shot.

When I click reply, the recipients emails get doubled up.

The ticket is not merged or anything similar. 

I checked the original email in the inbox (copy kept) and they are all in there as single, so no double typos ether.

Latest version 8213 is installed on Linux and I just restarted as well.

Kind Regards,

Per