Uber shaving tips

I just watched a passenger give me a $5 tip, 100 percent absolutely positive it was a $5 tip. a minute later, I received a notification as I was driving away that I had received a $3 tip. I figured that oh it was just another person tipping me and it wasn't her. I went back and checked the actual trip for the tip to send a thank you, and noticed that it was in fact the trip that I had just dropped the lady off for.. Thoughts?