> I wonder how come this issue never came up until now, in all the time
> since commit fb87d500, 9 months ago? What are you, Евгений, do that
> bumps into this issue, that other people don't do? Or does this
> affect only very specific packages?
I moved my everyday working emacs instance to 29.0.91 and got almost 2% completely broken packages.
I rarely delete really old versions from my ~/.emacs.d/elpa.
If your package-user-dir is cleaned more often, you may not notice that your loaded packages have slightly different old versions.
This can affect any package if it has few versions.