You can use apt-mark showhold to see what is held.
In my post I noticed issues with new packages in spite of holding 550 - including very similar packages to what you are seeing.
You'll need to go deeper and "pin" linux-objects-nvidia-like packages; e.g. create a file /var/lib/apt/preferences.d/99-block-objects-nvidia:
Package: linux-objects-nvidia-*
Pin: release *
Pin-Priority: -1
You might also need to do the same for modules (although I believe pinning objects will be enough).