So I went again with a Mid 2015 Macbook just over 2 weeks ago, with the
latest 12.6.1. Filevault enabled and so far so good, not quite counting
my chickens yet, but will update on any changes.
I have had this same issue on a Mid 2015 Macbook Pro, upgrade from
Catalina to Monterey (Just in Monterey support, I know, but in support).
I have wiped the Macbook and ran a fesh Monterey 12.4 install and logins
fine until I re-eanbled FileVault. Re...