grub-efi-amd64-signed version stuck, trying to find why

[AAF]

Dear Maintainers,

Happy new year first!

On unstable, apt upgrade gives these packages as held back:
grub-common grub-efi-amd64 grub-efi-amd64-bin grub2-common

because

grub-efi-amd64-signed : Depends: grub-common (= 2.12~rc1-12)

Where grub-efi-amd64-signed seems stuck at version 2.12~rc1-12 where 
grub-common is 2.12~rc1-12+b1.

Snooping around I found that the piuparts log shows:

0m15.2s ERROR: Command failed (status=100): ['chroot', 
'/srv/piuparts.debian.org/tmp/tmp7svj6391', 'apt-get', 'remove', 
'dmsetup', 'gettext-base', 'grub-common', 'libbrotli1:amd64', 
'libdevmapper1.02.1:amd64', 'libefiboot1:amd64', 'libefivar1:amd64', 
'libfreetype6:amd64', 'libfuse3-3:amd64', 'libpng16-16:amd64', 
'grub-efi-amd64-signed']
   Reading package lists...
   Building dependency tree...
   Reading state information...
   The following packages will be REMOVED:
     dmsetup gettext-base grub-common grub-efi-amd64-signed libbrotli1
     libdevmapper1.02.1 libefiboot1 libefivar1 libfreetype6 libfuse3-3
     libpng16-16
   WARNING: The following essential packages will be removed.
   This should NOT be done unless you know exactly what you are doing!
     grub-efi-amd64-signed grub-common (due to grub-efi-amd64-signed)
   0 upgraded, 0 newly installed, 11 to remove and 0 not upgraded.
   E: Essential packages were removed and -y was used without 
--allow-remove-essential.

Is this the reason why grub-efi-amd64-signed is stuck? (I would like to 
improve my ability to figure out why)

Thanks for your time
Andrei