Is there a limit for the waiting queue outside the vault?

I have 10 dwellers queuing outside my vault that I don't want to let in. I have 25 explorers and 200 dwellers in my vault. I also have two lunchboxes that I can't open "There are too many dwellers in the waiting line".

A few versions ago I had 10 dwellers waiting outside my fault, and could not queue the 11th, even though the radio room had "produced" another dweller.