Bug with sinks

Not really sure if this is a bug since it might be intended to be this way but It has been bothering me forever. When I have let's say two bathroom stalls and one sink and two duplicates go to the bathroom at the same time, or one goes past a sink the same time as another some of the dupes get past without washing there hands and it releases the germs, I wish they were a little smarter and would wait in line, I have tried using logistic circuits to make a one person at a time airlock but it won't work, they always get through and release the germs! I feel as tho this is a bug because I think it is quite obvious that they should wait in line, again I'm not sure if the Klei intended this but if not then it would be great to have and if it's a bug then it would be great to fix it! Anyway, love this game! Thank you, Klei!