today I sent you an interessting observation in a OnPremise Exchange 2013 (Cache Mode/CU14) with a Windows Terminal tenant and Outlook 2013.
I am a PowerUser and some of my collegeues, too. We have 20-25 different calendars, which we shared between us for different Projects and internal stuff. We don´t use public folders, only calendars, which is hosted by the project owner (personal Exchange Acc).
Since the last weeks we can track, that we have issues to access these calendars or to see elements. There is no period or any things we can´t say, like this: if someone use the calandar the other ones can´t see elements.
you can choose with the Cache mode: Your Mailbox, Shared Folder and Public folder.
Trust me, many other Mailboxes / Shared Folder / Public Folder or Mailboxes / Shared Folder / Public Folder with a large amount of items and performance issues with Outlook are mostly cache mode issues.