[0.973] Vadso City Invisible walls

Description:
in Alpha 8 over the land bridge their is an invisible wall in the air and will wreck all helicopters that fly near by

Steps to Reproduce:

take a heli and fly it at the area ! only tested in the Lynx

Screenshots / Video:

this is the original incident where i first noticed it
What the.. i dont even - YouTube

this is the recreated test
vadso bug! - YouTube

Tested On:
Happened on CIA
Retested on OD-S Public Server

-map name vadso
-game mode / layer cq std
-server name (if not dedicated list as local) CIA
-version number 0.973

Prof.