Shared mailboxes miss Inbox over IMAP using Share Toolkit

[krulfa]

Hello,

we use Zimbra OpenSource 8.8.12 with the latest relevant Share Toolkit.
All working as expected when accessing shared mailboxes over https:.

But if add account that has a shared mailbox using IMAP account into Microsoft Outlook, there is no Inbox folder within folder trees of shared mailboxes. Other folders in shared mailboxes are suprizingly visible, including Sent Items, and no errors are generated. The Inbox is silently missing. This is also reported by Android users but I have not took a closer look.

This may be related with the folder name mismatch: in English versions of the software, the name is always "Inbox", but in Russian versions it is sometimes named "Входящие" (a translation into Russian). Not sure where Outlook takes this from.

Please help to troubleshoot.

[krulfa]

A small screenshot is attached. Here >Info@ la... is a mailbox shared with the main mailbox using the Sharing Toolkit.
Note that folders Drafts, Junk, Sent, Trash, and even Архив (Archive) in Cyrillic are visible within the shared mailbox, but the Inbox is not among them in IMAP clients.

But on the http client Inbox is present.

Inbox.png (4.09 KiB) Viewed 2281 times

Inbox on http.png (7.78 KiB) Viewed 2281 times

[zimbramin]

Confirm.

On the outlook and thunderbird shared inbox folder is missed.