What is changing ComputerName?
UPDATE: Updating to 10.10.4 fixes this problem. In this point release discoveryd is replaced by the previously ousted mDNSResponder.

The originally supplied answer follows...

This is caused by an interaction with a daemon called discoveryd (that is present in Yosemite OS X 10.10.0 to 10.10.3) and the sleep proxies that are present within Apple TVs and Airports.

I outlined a workaround here; which is basically disabling "Wake for Network Access", which is also suggested in the post you linked to. You could also stop using your Apple TV/s and Apple Airport/s if you are in a position that allows you to do so.

9to5Mac reports that discoveryd has been dropped in OS X 10.10.4 beta and replaced with the previously ousted mDNSResponder daemon. So this problem should be fixed in OS X 10.10.4.