Audio problem: Spy: The Spy has a voice response trigger sometimes when getting hit by the Sniper's Jarate (jar of piss), where when he sees it's all over his nice suit he yells "Jarate!? Nooooooooo." This same voice response will sometimes be triggered if they spy is hit with the Scout's Mad Milk, even though it's not Jarate.
Audio problem: Engineer: Taunt Dueling Banjos: If you view the this taunt in the inventory and inspect it, the music will get stuck in a loop and play forever until you leave the game or use a console command to reset the sound.
Audio problem: Engineer: Taunt Dueling Banjos: Sometimes when using the alt fire or primary fire buttons to change the speed of the Engi playing, will cause the music to stop with only silence. This can be fixed by leaving the taunt and activating it again.
Audio problem: Soldier: Shooting with a Soldier weapon followed by a quick weapon switch will result in the sound being cut off. This excludes melee weapons.