Strange ending

The BR was about half way to 1st when she and the 1st base coach began jumping, hugging, celebrating, etc and she never went any further toward 1st. The runner on 3rd touched home plate. The BR and the remaining runners went into or over to their dugout. The offense began lining up to shake hands. The DC kept his players on the field, near 1st base, and then called out to the umpires that the runner had not reached 1st base and she should be out. The umpires discussed things and declared that the run counted because the defense had left the field, which they very clearly had not as they were all still standing on it. However, the BR and other runers had without question left the field.

It seemed to me that the run should not have counted not only because of the 1st base coach being on the field doing her dance with the BR but also because the BR never reached 1st base.

Ed