Transport Boats Depositing Armies in Areas They Normally Shouldn't Reach
I've walled off several cities in my worlds to prevent them from being invaded in the past. Invading transport boats can sometimes deposit their armies WITHIN the defender's walls even if the city is pretty far from the coast.
This results in enemy armies somehow "teleporting" into the walled city and invading it even if they're supposed to be protected by the mountain barrier/wall.
I only have one screenshot of this instance but it has already happened a number of times already and often when I check back on the city I want to keep independent they have either already been invaded or destroyed by another race.