OMFG YES!!!!
O Grenades no longer teleport into the void before exploding when they are shot into vents (bug #530)
My bug was fixed, and I was right!
For the less informed...
This bug caused the 'invisible nukes of doom' in vents that'd annihilate everything near it, through walls, whatever. It had been a major bug, people knew about it, but no one really knew why.
When a grenade explodes in half-life, the engine will detect if there are any walls (brushes) nearby. If there's nothing, it removes the grenade projectile, and spawns an explosion.
If it does detect a brush, it will teleport a virtual point slightly above the grenade, based on a calculation that factors in the power of a grenade (more power = higher in the air). Then it spawns an explosion at this point.
Another guy calculated it out, figured out that if it was using default half-life mechanics, it was teleporting the grenade a hundred or so units above it. I pointed out that this was larger then the size of vents in NS. Then I mentioned that half-life will completely remove the outside of a map (the 'void' area) that you can't see. So for all intents and purposes, a grenade detonating in the void, to the engine, would not see any walls (since the backfaces are completely invisible and non-existant to the engine) nor entities, so it was the equivilent of the grenade exploding next to you in a large open room.