Here's the situation around Vitebsk in turn 6. I just drove panzer group 3 as "hammer" north through that massive blob of soviet units, that spawned after turn 3, hoping to create a pocket. But alas, terrain was too bad, and the Ninth army as "anvil" got stuck halfway through.

I thought, ok, unable to close the pocket this turn, but since I cut all rail lines and terrain is bad (forests, swamps, rough and lots of ZoCs), they should at least get a slight supply shortage, they make a move out but their MPs won't be enough and may be next turn I can close the bag.
I hit end of turn, expecting a bunch of Soviet divisions with at least a yellow supply outline. But instead, I saw this picture:

Now the question is, where are they gone, and how? May be I missed an evacuation button somewhere in the massive interface (as I said, I'm new and still learning). Or is that a bug?