Namespace INBOX overlap with Public Folder Namespace

[kingfisher77]

We have a new setup with Dovecot 2.3.20 and Roundcube 1.6.1.

When we configure special folders like Junk and Archives in some Public Folder with the attribute special_use = \Junk or special_use = \Archive, Roundcube gets out of step.

The junk or archive folder of the first namespace after INBOX is visually marked as a special folder in the user account (corresponding icon). If a new user is created in Roundcube, the Junk and Archive Folder of this Public Folder - the first one after INBOX - is used as the Special Folder for the user!

There is obviously an overlap between the namespaces INBOX and Public Folder. All other MUA we tested do not have problems with our setup.

Is this description sufficient? I would be happy to provide more information. Which?