As of now, the only time I'm getting these messages is when I start a VM; the userif up/down are still happening, but I'm not seeing a drop in the network on either the VM or my host PC (which should be the normal case. In both previous instances, I was getting notifications from NetworkManager about the disconnects (host and guests).

I really appreciate all of your responses. My only real concern going forward is why this is still being brought up after 8 complete revisions of the VMware client.

One more thing: in doing a simple search of kernel: userif-3, almost every system referenced in the links have VMware installed. In fact, after checking my system journal, I didn't get my first message until after I installed VMware.