My suggestion: reduce the number of farmers you can hire to maybe 4 for either harvesting or plowing. When I am hired to work a farm with 7, 8, 9 or 10 other farmers, I immediately click off to avoid "collisions" etc. I think that is the most simplistic answer: reduce the hired hands to no more than 4.
Thank you for taking into consideration everyone's concerns about the most recent change. It really was way too frustrating.
