Valve has finally patched a 10-year-old Team Fortress 2 (TF2) bug that caused client and server hitboxes to fall out of sync.
Once activated, the bug would mess up a player's hit detection, meaning they might miss a seemingly simple shot, or actually get hit despite having successfully evaded an incoming bullet.
According to Reddit user Sigsegv, who reported the bug to Valve after it was unearthed by a member of the TF2 Classic dev team, the issue was "relatively huge" and has been in the game since it first hit shelves in 2007.
"Basically, merely by changing class, pose parameters could get seriously screwed up, messing up how the hitboxes animate on the server side (which, in turn, messes up hit detection)," explained the Redditor.
"The human player models mostly just had messed up leg animations, because only the 'move_x' and 'move_y' pose parameters got swapped.
"The MvM robot player models have, uh, slightly more different permutations of pose parameters, so the consequences (as you can see in the video above) there were much greater."
Valve has confirmed that the bug has been fixed in the latest TF2 patch notes, quietly explaining it has nixed an "animation bug that would cause the client and server hitboxes to become out of sync."