I started a new game, drove around Black River with a scout and identified all watchtowers and picked up all upgrades. Did the same thing in Smithville Dam. Did a few on Drummond Island then went to Island Lake to get one upgrade. Now i have no tasks. Nothing shows up on my quest book, and there are no Yellow Boxes on the ground for me to pick up the task. But, if I park on a spot that a Yellow Box should be, and restart the game, I get the Show Task confirmation and then I can get that one task.