Hi Mark,

>> I cannot test sysvinit on Buster, because Debian Buster does not have
>> the sysvinit-core package!!!!!
> I think it does:
(deleted)
> But no matter, I was just trying to narrow down possibilities.

Sorry, you are right and I was wrong.
Actually, apt-get install sysvinit-core reproduces the same symptom
with Debian Buster with sysvinit-core.

Best regards, Ryutaroh