Units go backward / Get stuck in certain movement

This happens often to me.

The unit will get stuck in some sort of movement pattern where it wants to go backward to where it came from before advancing.

Idk how to explain it, but lets say i try to move a unit to nodes over. The unit will backtrack to the original node before moving the two nodes forward.

or it will get suck going into an enemy city. No matter where i tell the unit to move, it becomes locked onto the city and refuses to take the path of least time. it will go out of its way to go to that city first, and THEN go to where your telling it.

its frustrating because i scout a city and then get stuck because i don't want to attack the city but the unit refuses to take any path other than through the city.