I've received a quick update from development on this today and wanted to reach out here to give you an outline of our next steps on this. First, we did confirm these issues are stemming from the fact that there are multiple MAPI accounts within a single Outlook profile, as only the first MAPI account added will be capable of opening/mapping shared resources. This issue has been escalated and is being reviewed/worked by our development team at this time. 

With that being said, you can work around this by utilizing separate Outlook profiles for each MAPI account. This is done by opening Control Panel>Mail in Windows, then clicking the Profiles option towards the bottom, and configuring the settings there to prompt you which profile you'd like to load on each startup. Finally, separate your two MAPI accounts into their own profiles and you should then be able to open shared resources as expected. Please keep an eye out for release notes on the long term fix as well. Have a good one!