I don't know that I agree that's logically correct. the output from the init script should be going to to stdout. It is *not* error output from DKMS's kernel postinstall script, so it shouldn't be on stderr.
If it's not happening while DKMS is running, then before loading debconf in nvidia-common, I think nvidia-common should flush stdout to prevent anything deferred showing up.
I don't know that I agree that's logically correct. the output from the init script should be going to to stdout. It is *not* error output from DKMS's kernel postinstall script, so it shouldn't be on stderr.
If it's not happening while DKMS is running, then before loading debconf in nvidia-common, I think nvidia-common should flush stdout to prevent anything deferred showing up.