I have just got the excellent GT:OS bundle at Bundlestars and I am seeing the same thing.
I am a fan of Chieftain so I set up several quick battles with a small company group of Chieftains and M113s (playing FV432s), against a dug-in Red infantry platoon. I tried several different maps, and it was great so see, almost like being able to play BAOR -v- WARPAC.
But...the Chieftains are totally unresponsive to Move or Attack orders. The APCs are fine, but the Chieftains will not move, except that they may creep forward a few yards then stop completely.
I tried this on several different maps, with the same result. Changing the friendly skill level from Normal to Veteran makes no difference.
I replaced the Chieftains with M60A1s and they DO respond to orders, in exactly the same quick battle where the Chieftains would not move.
There's something wrong here.