Local name changes every 10 - 20 minutes
This happened to me at work when we were using individual wireless access points, each acting as a DHCP server: the MBP was, at different times, catching its signal from these different access points, depending on the location and the strength of the various signals. We changed to use a central DHCP server, and set the access points to extend an existing network, and it solved this problem, as well as a similar issue where the user would get messages that the IP address was already in use.