Minor Tech Tree Bug

[Stuie]

I started a game as the Persians and was a bit too agressive early... anyway, long story short - I exited to the main menu from my Persian game and started a Japan game. Now the bug:

When viewing the tech tree in my Japan game, the Persian Immortal unit still appears and my Samuari does not. This happens every time I start a new game having played a previous one without restarting Civ 4.

 

[MxxPwr]

I've noticed a variation of this bug in hotseat multiplayer. In my case, Player 1 is the Mongolians; Player 2 is the Persians. Player 2 sees the Mongolian Keshik in the tech tree instead of the Persian immortal.