Often times I find that many (sometimes, it seems all) of my contacts will appear as offline or away, and therefore automatically left in the "Away and Offline Contacts" section, until I actually view the user in the contact list. When I expand the "Away and Offline Contacts" section, and as I scroll through it, the users' status icon will initially be grey. But then, very quickly after a user is shown in the list, their status will update and users who are actually online will turn green and be automatically moved to the appropriate group.
Occasionally, though it seems less often, the reverse will also occur - when I scroll past a bunch of online contacts, a lot of them will suddenly switch to offline/away at once.
This occurs with Lync 2013 on both my work computer and my home computer, both using the same account and servers. So, I'm not sure if this is a server-side issue or a client-side issue, or a little of both.
What can cause this? Are there things that and end-user can do to troubleshoot and fix this, or does it require Lync/Exchange Administrator assistance as well?