Apparently you've never heard of respositories or anything like that.
If something is reported done, it provides zero guarantee that it's going to be in a particular build of a game. It's possible that the build shown was off of a different branch that didn't include the fixes. Or maybe it was built off the main trunk, but the completed fidgets hadn't been merged into the main trunk yet.
You need some actual understanding of software development before you can actually make a claim like that.
"Latest Build" doesn't mean anything. Heck, since you have demonstrated your extensive knowledge about Valve and Half-Life 2 in the past, surely you remember that reading in the news how the stolen build on Gabe Newell's laptop was very out of date.
It is also possible that, given the relatively short duration, they didn't want it to go through without some QA looking at it. You'd rather they use the "latest build" (without understanding what that means)...maybe they'd rather not put stuff into the demo build (assuming the people making the demo build had access to it...what with being in a different country and all) that has only received any testing from the programmer that implemented it.