Here is the Minor Planet Mailing List from January 2; describing the case in real time: https://groups.io/g/mpml/topic/110402021#msg40127 .
This happened before, in 2018 right after Elon Musk's marketing stunt, and the Falcon Heavy upper stage was identified and removed from the asteroid list.
The current case was because of additional observations being reported and a cross-check initially failing to make the correct linkage.