ORIGINAL: Philippe at bay
When I was still playing the Barbarossa scenario I noticed that to make encirclements work I would have to make sure the pocket didn't include a city, because next turn the troops in the pocket would be beefed up to full strength with reinforcements.
Perhaps it would make sense to put some kind of limitation on reinforcements to units that can only trace back to an isolated city. Given the scale of the game I can understand why an isolated Bialystok would be able to produce something from an emergency mobiliztion of workers despite being cut off from Stavka.
As things stand kiel und kessel tactics don't feel right. I shouldn't have an incentive to storm cities with my Panzers.
This feature is already in place, so it may be then that we have a bug because any isolated resource, unless it is an Industrial Center or Primary Supply Center, shouldn't provide sufficient supply to any friendly units to reinforce to full strength unless a HQ is present.
Even then, if the HQ is at low strength then it still may not suffice.
Can you please check and report what the supply status of these isolated cities is where units are reinforcing to full strength, and which ones they are?