Not sure if its something I didn't understand but I started to move my units into the regimes territory and the red hexagons appeared as usual but when I clicked on them to enter his territory I didn't get a warning and a question as to if I wanted to invade but it allowed my units into the territory. During the history phase after I ended turn it showed the pathway I made in dotted white lines but when the turn started it just had my units surrounded by his territory and my units out of supply. I then clicked again on one of my invading units and as you see in second picture below that I got red hex again but this time it gives me option to invade. I choose to invade and the spots where my units were still showed as their territory so I had to move a unit forward and back to spot and then it made it my territory.
