The Dupes will continue on certain tasks indefinitely if I don't cancel them. Tasks include mopping,sweeping, digging and building it appears randomly sometimes. They will not complete digging tasks if a mineral (the ball that appears after digging, that you can sweep up for resources) is on top of it or if there is a plant and when I tell them to sweep/harvest/dig the mineral or plant the task will go on indefinitely too. Sometimes if you ask them to sweep they will and that will solve the problem but some minerals (stuck in holes you just dug out) will stay there and if you try to build tiles over them or sweep the mineral up the dupes just build indefinitely over them. The first time I played the dupes would be walking over invisible obstacles and one dupe got stuck on top of a mineral ball in the air.