At first it seemed to me that the problem was fixed at 1.82 (first report was closed by me), however I re-encounter it again and again.
When the tank or othe vehicle has an active current waypoint or order of AI-commander and player is commander ot this vehicle, then in menu 1/8 - the AI not will execute the "Next Waypoint" command. After pressing the 1/8, the commander (player) will tell the driver - "move to ....coordinates", but the driver will ignore this command.
This bug was added in the update 1.80
If I open the editor and put my vehicle there with only one Waypoint Move, then it will work!
But stability is immediately destroyed if you use it in conjunction with several different waypoints!
When I play my old missions, then it stops working. I tried to recreate these conditions for you.
In my mission - If I use a bundle of waypoints (Join+Join and lead), then the AI stops understanding the "Next Waypoint order". Prior to the update 1.80 it worked perfectly! Now something is broken.