When you open a saved game, all the fishing huts have the red “no fish in range” warning icon. If you move the map or interact with other buildings, the warning will stay, even though the worker goes out to fish. If you click on the hut, all the values show as zero in red font. But if you click on the hut and click the circle to reset their radius (even if you set it exactly where it had been) it will clear the warning. Not just on the one you interacted with, but with ALL the other fishing huts on the map as well.
Have tested it so far in repeating by:
- Closing the game without interacting with anything, not saving, and then reopening the same save file
- Cleared the alert and played for a few hours, saved and closed for the night and it happens again afterward.
The game says I am running random generated map seed 69EEF025DC7, if that helps any in tracking this.