Here's a minor one : if I have a plan that Recycles Appliances until my scrap is X, then immediately attempts to upgrade a tool via a scrap expenditure, it'll run about one second of the upgrade task before reverting back to the Recycling one. It does this a few times, until my scrap is over X plus the cost of the upgrade, at which point it lets the upgrade task run in full.
Put another way, it rechecks the completion condition for the task it finished last step about one second into the new one, then reverts if that user determined completion criteria no longer pings as True.