D6 package isChanged/compare loose method bug

> If I follow the steps below:
>  - Start with a fresh image.
>  - Install a package that contains a loose method that replaces a
> method in an existing package.
>
> ... Then the existing package is not marked as changed in the Package
> Browser.
>
> Similarly, if I follow the steps below:
>  - Start with a fresh image.
>  - Create a new repository.
>  - Add all loaded packages to a newly created repository.
>  - Install the package that contains a loose method that replaces a
> method in an existing package.
>
> ... Then if I right-click on the existing package (the package that
> lost a method) and "Compare with" the original package edition, it
> says: "No changes were found between loaded package and edition in
> repository."
>
> FWIW: If I then change the package of another method from the existing
> package to the newly installed package, then the Package Browser shows
> the existing package as changed, and "Compare with" brings up both
> changes.