What is Late harvest, why and how to prevent this?

I have following farms, and all of them have this “late harvest icon” which I have no idea what kind of impact it has on my town and how to prevent this?

The 3 farms next to each other have rotation of foods

1st Farm

2nd expanded farm

3rd farm

4th farm is just Flax and still trying to figure out how to increase fertility naturally :smiley: