I'm having an issue with a bunch of users that access a public folder calendar by adding it to their public folder favorites.  This adds it to their "Other Calendars" in Outlook.  The public folders are disappear as users click on these calendars.  If they restart outlook and go to public folder favorites and click on the public folder calendar, it adds it back to "Other Calendars".

Has anybody seen this issue?  It seems to be happening only to users who use multiple public calendars.  It seems to be sporadic...but consistent.

Yes, but if you want to get back public folder

In outlook 2013

go to below options such as Mail Calendar People Tasks and then some ........  ( dots) click the dots -> then it show some options shortcut, Folder,notes and navigation options. Then click Folder -> Public folder will appear under your mailbox again.

Additional Tips

In Navigation option , you can increase the number of visible items, by default it is 4. increase to 6 then folder option will show under your outlook

Regards,

Joby