Attachments duplicating in reply and forward

[markomal]

Hi All,

I have a strange problem with one mail account. Using zimbra 8.8.15 and web client

When replying or forwarding emails that had attachments, and then add a new attachment, all previous attachments get added (in duplicate) along with the new one.

This happens on just one account on the server. All other function normally. It happens regardless of which computer or browser this user is logged in.

Any help is welcome.