I didn't make it!
This bug is easily reproducible. Choose the "anti-tank" kit from any faction (German, British, etc.).
Get out the big anti-vehicle gun and lie down by pressing Z.
Now, zoom in with the gun while lying down. After you're zoomed in, stand up while staying zoomed in.
Here's the bug: you can't un-zoom!!! You have to lay back down, right-click to unzoom, then stand back up!!
Very frustrating, because when under attack, you will forget to unzoom while trying to run away, and find yourself walking slowly with your face glued to the ironsights.
This is a known bug, but I don't believe it can be fixed due to how the AT rifles and machineguns (like the mg34) work. It is yet another limit of the BF2 engine. :(
If that happens again, you can also switch to your pistol or another item in your inventory to get 'unstuck'
Feindlichen Panzer gesichtet!
1st November 2004
Posted several times before: It is NO bug. It is intended to prevent people from firing while standing. Same as with the mg34 but regretfully not with the bren 8puuuh I had to mention that ;)
Helmchen, he was talking about un-zooming, not zooming :) It's indeed a bug, but I think nothing better can be done on bf2 engine.