My first move would be to verify if Valve is investing money, or just copying some mods when it repairs bugs for Half-live.
My knowledge in videogame is limited. BeamDog with Baldur's Gate 1 and 2, or Diablo 1 with the Belzebub mod, all benefited greatly from the free web culture or mods.

My understanding is that Valve employees get to do practically anything they want (I guess that's why they don't make games anymore) so if someone wanted to go dig into their backlog and fix a random bug they can. This actually isn't the first time something like this has happened in fact.

Half Life is a classic.

Patch released for the original Half-Life? Sounds like Half-Life 3 confirmed to me.

Anyways, Half Life is still loved and a lot. It even creates a new meme: Youtube videos with the SFX of Half Life.

Hi: Jo.

Can you enable DISQUS on this site. It's easy to implement and it's better than to login on facebook or google+ (is is still alive?).

Possibly the fix was forgotten somewhere, and recently rediscovered and released

Someone at Valve killing time, maybe?

I believe that employee is an Half-Life fan and had some bugs annoying him. Did some bug fix on his break time.

This comic reminded me of Plants vs Zombies and how EA bought it just to milk the franchise while removing the people who made the first game a success.