[2020] GAME BREAKER

You can use these 3 admin commands to reset the nutrient layers immediately:
"/sim setlayer Potassium, 0.6, 0.9"
"/sim setlayer Nitrogen, 0.6, 0.9"
"/sim setlayer Phosphorus, 0.6, 0.9"

The commands above should fix this. The yield layers are generated from the nutrient layers. If there is no yield layers for plants then nowhere on the world map there is a nutrient span that works for these plants. You need to wait a bit after using the command, it will slowly fill the layers.

If this still doesn't fix it, a screenshot of the yield layers and a screenshot of the nutrient layers at the same areas would be helpful to investigate this further.