Users are accessing the Zimbra mail server using the mobile login (e.g. from a phone) and every now and then only some of their folders show up. This also happens in windows 8 while logging in with the mobile login. Is there a fix for this?

recreation steps:
1. Login into your Zimbra account (one that has multiple folders)
2. Go to your inbox
3. Click on "folders"
Once in a while some of the folders will not show. *NOTE* user has less than 100 folder
If you click on the actions pull down menu, all folders show up in there even when the folders don't show up in the root folder.

Thanks