Bees fighting over water

It is amazing how much more observant you become once you start keeping bees.

Today I was in the garden and I noticed two bees ferociously fighting on an irrigation dripper. One was probably ours, an Italian, the other was much darker so from another colony. Water is not scarce, we have plenty of drippers in service and various other water sources around. It was a rather cool day.

One was pulling the other from the leg away from the dripper and ended up in a ball, at the end the dripper stopped watering and none of them had any water.

I’m familiar with robbing, but is this kind of fighting common too?