The blogs changed systems on May 12, see:
https://www.morrissey-solo.com/blogs/blogs-imported-into-new-system.4422/
I missed the feature of the previous system in my testing that allowed who could view the entry and how it got converted. My apologies! The blogs aren't used that much to begin with and I didn't know anyone actually used that option. Removing the posts is probably the best option if you didn't want those users to view them.
Thanks to further info forwarded from FWD.