The more the base advances, it seems that duplicants stop doing tasks they have been doing the entire time to focus on other things.
This was especially prominent to me when I had a mushroom farm going. At some point, duplicants would stop fertilizing the mushrooms, no matter how high i set their priority.
Steps to Reproduce
1. Have 12+ duplicants 2. Expand the base more and more 3. Let enough time pass
This issue has not been confirmed by a developer yet.