Guix upgrade leads to different hashes

[Oleg Pykhalov]

Hello Guix,

Something strange happens on my machine with upgrades.  I check for new
available upgrades with dry-run and get “available upgrades” all the
time.

Check upgrades.
--8<---------------cut here---------------start------------->8---
$ guix package --dry-run --upgrade --verbose
The following packages would be upgraded:
   translate-shell      0.9.6.4 → 0.9.6.4       
/gnu/store/v9d7c3pfyfyw24v576a8dacvr77xc5sw-translate-shell-0.9.6.4
   …
   emacs-pdf-tools      0.80 → 0.80     
/gnu/store/vi536ni0dz8mdkfzhlhn00w1gbf0jcjb-emacs-pdf-tools-0.80

…
--8<---------------cut here---------------end--------------->8---

Upgrading...
--8<---------------cut here---------------start------------->8---
$ guix package --upgrade
The following packages will be upgraded:
   translate-shell      0.9.6.4 → 0.9.6.4       
/gnu/store/v9d7c3pfyfyw24v576a8dacvr77xc5sw-translate-shell-0.9.6.4
   …
   emacs-pdf-tools      0.80 → 0.80     
/gnu/store/v8qn1r6hgp1gsavw66xbcnvvrli3pksx-emacs-pdf-tools-0.80

…
--8<---------------cut here---------------end--------------->8---

Check again.
--8<---------------cut here---------------start------------->8---
$ guix package --dry-run --upgrade --verbose
The following packages would be upgraded:
   emacs-pdf-tools      0.80 → 0.80     
/gnu/store/vi536ni0dz8mdkfzhlhn00w1gbf0jcjb-emacs-pdf-tools-0.80
   …
   translate-shell      0.9.6.4 → 0.9.6.4       
/gnu/store/v9d7c3pfyfyw24v576a8dacvr77xc5sw-translate-shell-0.9.6.4
…
--8<---------------cut here---------------end--------------->8---

If I upgrade again I'll get same hashes as in “Check upgrades.”.  Like a
loop.  It's not related to grafts, is it?