This has been going on for as long as I can remember. My Half Life 2 game, which I bought off of Steam, has some broken animations. The most notable example is when you get teleported into Breen's office. In other gameplay videos I've seen, Breen is supposed to jump up. However, in my version, he stays sitting, looking up at you.
Next, when you teleport back, he is sitting down also.
Is there a fix or is this courtesy of the Steam edition?