At a glance, it appears to me that grub-efi-amd64-signed is missing a dependency on grub-efi-amd64 | grub-pc, which I believe was discussed as a requirement but seems not to have been fixed in the version that was SRUed.
At a glance, it appears to me that grub-efi- amd64-signed is missing a dependency on grub-efi-amd64 | grub-pc, which I believe was discussed as a requirement but seems not to have been fixed in the version that was SRUed.