The bio and notes fields did go under a complete overhaul in order to support oEmbed. Basically they are much more inline to how WP sanitizes and escapes page.post content.
I looked at the code again, before and after the change and I can not figure out why the
" are being slashed.
What I need is a temp admin account so I can log in and debug to locate the exact point that the slashes are being added. Once I know that, fixing it will be trivial.
My best guess at the moment is that HTML was saved slaed in the db in but that does not make sense because it wasn’t being unleashed in 8.2.8 and older.