I don't have an answer, I'm adding to your question because I had the same thing happen a couple weeks ago. I was inspecting a couple of my backyard hives when I saw a ball of bees in front of one of the hives I'd inspected. I moved bees to find a queen in the middle being attacked. I put her in a queen catcher and took her in the house, into a mesh bug holder with a couple other bees from a different hive. They did not attack her, but she died the next morning. The hive she was in front of still has a laying queen, so I have no idea where she came from.
My only guess is that they superseded her from a different hive I'd inspected. In fact, a different hive that had a failing queen, that same inspection I captured that queen because I saw a supercedure cell. That second queen was quite large, and now I wonder if I captured a newly mated queen from the hive and the balled queen was it's old queen. Does that make sense?
In any case, I suspect but I don't know for sure, that the balled queen was being superseded. I hope some experts answer these questions.