Win 10/11 file history is malfunctioning after an update why has not Microsoft fixed this issue yet?

This is a separate issue from the "last backup time not updating" problem discussed here, but it may help anyone whose File History drive keeps growing because "Clean up versions" always fails with "Element not found" (0x80070490).

I found the root cause by live debugging fhmanagew/fhengine with public symbols. fhengine!CSessionBaseRW::RetireFileVersionsOnTarget binary-searches backup-set IDs, but the catalog allocates those IDs in steps of 2 (only odd IDs exist), so the midpoint often hits a missing ID and the whole cleanup aborts. Microsoft already shipped a fix in the same code, the WIL feature FixFileHistoryIndicesForCleanup (feature ID 61540776), but on my PC it is explicitly disabled by servicing at Security priority.

After overriding it with "vivetool /enable /id:61540776 /priority:userpolicy" (note: the default User priority is NOT enough) and rebooting, cleanup worked and freed about 428 GB.

Feedback Hub (please upvote): https://aka.ms/AA140rbi