We have several sinks at work that I was testing today for slow drains and noticed that when I turn the hot water on and let it run, it builds up in the bowl and drains slowly. If i turn it over to the cold side (with the hot water in the bowl) it starts to drain faster. Once it's drained if i just let the cold water run it continues to drain quickly, barely even backing up. As soon as i switch back over to hot it starts backing up again. Found it to be interesting. Is this a sign there's something in the line? or something to do with the strainer in the bowl?