Why are Russian BMPs flying like helicopters?

The above screenshot was taken from someone playing the 1985 Cold War Campaign's Counterstrike mission. Instead of you and your squad landing by parachute, people with this problem are landing by BMP.

What could be causing this? If you upgraded to OFP version 1.30 from one of the 1.2X beta versions, do it again, soldier! If that's not the problem, try removing any unofficial addon files from OFP's ADDONS subdirectory, restart OFP and check to see if the problem's resolved.

So far I've seen one player confirmation that this problem was caused by Devil's Parachute addon, another one saying it was caused by Devil's Civillan Vehicles addon and yet another one blaming Devil's Special Weapons addon. Hmmm........ I think I see a pattern here.

If you've identified other addons that cause this error, let me in on it.