Go to a Tinker planet that is near, but not at, maximum population ("nearness" to maximum isn't necessary to reproduce, but it will make reproduction much less tedious)
Set production to "manufacture population".
Queue up "trade" (or "research" or "mining," or really anything).
Hit next turn until manufacture population cannot proceed because your planet is at max population.
Expected behavior: it will go to the next queue item
Actual behavior: the queue remains untouched (so you still have the next thing queued up), but your 'current production' item is empty.