This was found in MongoDB testing on 6.0. There is an initial investigation in the build failure ticket. Here is a short description:

There is a panic when evicting a page, with the ret=EBUSY error with description, reconciliation failed after building the disk image. This is on the file file:collection-48--8990563129455281788.wt. Also, this is when the server is shutting down and a shutdown checkpoint is waiting for the eviction to finish on the same file.

From an initial investigation most likely the EBUSY might have come from trying to insert into the history store for the page. But needs more investigation. More details in the BF