It says in the quote that only the last 64 bytes are used to seed the CSPRNG so what is there to worry about? The first 12 bytes that remain constant aren't used to seed the CSPRNG. Maybe they serve some other purpose.
Although they aren't used to seed the CSPRNG they must be related to it, or they wouldn't be included in that registry key value. If the twelve bytes represent the differing entropy sources found and used on a particular computer there might be a security risk if an attacker reads them. On the other hand they might represent a unique identifier, in which case it doesn't matter if an attacker reads them.
I'm probably worrying about nothing, but I'd like to know WTF they are for.