I just saw a bug where I could not pass through my own units.
The problem happened on a port where I wanted to pass through my units to attack an enemy city. The map looked like:
Water|Port|City where the city was located right next to the port so that an attack from water was possible if you had 2+ moves left after reaching the port since it only requires 1 move to attack a city. I had units sitting exactly on the port from the prior turn. But I wanted to soften up the city first with another stack in the water. I created the move path to the city and it showed I could reach with 1 move left. But when I clicked the move units button nothing happened. I tried several times with no success.
Finally I moved my units on the port off to a square next to the city. Then I was able to use the water based units to attack the city as I expected.
KGB