Yes, this.
I had a girl dropping softies as she went into molt and there was always a telltale wet spot in the shavings even after the birds had cleaned up the mess.
One day you'll find that, suddenly, they only use that nest.
Chickens are weird that way.
Mine favor the boxes on the left. Then the boxes on the right. Then the middle. It's beyond my comprehension why a given hen chooses a given box.