I can't say that the issue was started by KAV but the timing lines up.
After installing KAV a user who often is away from his computer hours at time now finds that his computer looses his network connection temporarily when he comes back to his PC. This isn't an issue with Outlook which in seconds restores the connection. It causes a problem with a database application that needs a constant network connection.
Is anyone else experiencing similar issues?
Yes I've seen this on a couple of machines too, Windows 7 x86. Although I'm using KES not KAV, but it did start happening around the install date.