While observing the animations around my base, I noticed that when a farm is on the border of my screen, its windmill flickers in and out. These three screenshots are taken in order. You can see the progress of the other windmills on the farms that are fully in the area of the screen. With the two farms to the lower left, the windmills abruptly disappear, and then just as abruptly reappear a few moments later, in their appropriate position. This happens twice per cycle as the windmill makes a full rotation.
If it matters, I’m playing on a Samsung S9+.