How many villagers do you have? If it's 10 then you shouldn't need to worry. The game won't register you as having 9 villagers until Punchy's house has the moving out sign. So your visitor's void would have been cleared upon their arrival because you had 10 villagers. Now if you had another visitor after that, they could deposit a voided villager. That could even be corrected as well as long as you pick up the dreamie within the same game day, as the villager you've asked to move in will overwrite the villager sitting in the waiting/void spot. This will *only* work if it's done on the same game day though, otherwise the voided villager moves out of the waiting spot and actually begins queuing up its days to move into town ie the game now counts you as having 10 full villager spots.
Hope that helps!