What if you click the Client Version column again to sort top down? Does it put it in order than?
But yes for me 12.1.671 is at the top so my guess is this is by design.
I can see 12.1.671 being first but than 12.1.1101 than 12.1.2015 not 2015 ahead of 1101.
You can always run the computer status report from the Monitors page and export to CSV than drop into Excel and sort as needed. Probably not what you're looking to accomplish but a quick workaround I suppose.
I would suggest assing this in the Idea section to get it changed.