Robins nest early, raise that family then start a second nesting.
A question... what is the tree? I've noticed that Robins choose a conifer for first nesting, then follow with a deciduous tree for the 2nd nesting.
They started building it in the elbow of my eavestroughing. I noticed there were no eggs in it, so I took it down as it was in the highest traffic area of my deck. Side entrance, BBQ, dog play area, etc.
They then started building in a maple tree just beyond the deck. The main building material was moss