Team Fortress 2's latest silly business sees the game crashing because it thought players were Gordon Freeman

pcgamer.com:

Team Fortress 2 just received a huge update, upgrading it 64-bit, finally bringing the 17-year-old shooter into the modern age of gaming. But in true TF2 fashion, there was a problem that no one foresaw: the game kept crashing because it thought players were Gordon Freeman from Half-Life. 

The issue has since been fixed by the latest update on April 22, and all the patch notes reveal is: «Fixed a crash under 64-bit caused by some custom HUDs using Half-Life 2 HUD elements which assume the player is Gordon Freeman.» It's a bit of an odd outlier, sandviched between ABI compatibility issues and snd_cull_duplicates command not working. I nearly glossed over it myself.

This issue seemed to only affect players who'd customised their HUD using elements from Half-Life 2's UI via mods and the like. But this issue isn't entirely fan-made, as several custom HUDs use Half-Life 2 files that are already present in TF2, which is what confuses the game into thinking you're trying to load in as Gordon Freeman. It's also pretty common for Half-Life 2 and TF2 to have some overlap anyway since they both work off Valve's old Source engine.

While this update is pretty weird, it's not one of the strangest fixes we've seen for TF2. In 2014, one patch fixed a bug that teleported players to hell, and in 2022, there was an issue where the game would crash if Sniper tried to eat his gun (this happened if you switched to Sniper while Heavy is eating a Sandvich). The complexity of TF2's 'Source spaghetti' or 'spaghetti code' has been joked about for almost as long as the game's been out. There've also been issues where characters could hold multiple weapons at once, as well as false stories of the fabled coconut.jpg, which was thought to hold up the entirety of the game's code.

While the coconut.jpg story might be a tall tale, take one look at code comments from Valve during the development of Half-Life or TF2, and you can understand why it fooled so many. Some of my favourite comments include