ORIGINAL: Yaab
I think the Allied AI on 7th Dec has its orders issued as well. I ran the first turn as Japan and on 7th December,a Chinese DB-3 unit from Changhsa bombed Nanking. As Allies I can only issue orders on the next day, on 8th December. The AI units in questions probably started packing on 7th December, and not on 8th December.
This very well could be, but I am starting to think there's a bit more to it than that.
I just reopened some old saved game files but from the Allied side. I opened a file for the start of the Dec 8th turn and took a look at the Indian brigades in question. They were located in Alor Star and in Rest mode. I then opened the very next turn (start of Dec 9th) and they were in Taiping in combat mode (and recombined with the other units of their division). So, it looks as though the AI doesn't even need to pack or unpack. Strat mode appears to be an instantaneous thing for the AI (unlike for a human player where you have to wait a minimum of three days - one day to pack, one day to move and a third day to unpack). It looks to be completely skipping the pack/unpack process.
Now I understand that opening games from the opposite side can do some weird stuff to the files, but you have to admit this looks a bit odd and lends some weight to the idea that the AI is using a different, less restrictive process when it comes to moving units in Strat mode