Hello,
This has started happening since the latest patch: When I try to prepare my cleric spells after a long rest, everything in the spell preparation UI seems to be working as intended and I am able to select the desired spells. After the rest is complete however, the spells available are the ones that appear as default before I started changing them. (In my case it's really easy to notice as the defaults always include detect evil and bane, which I never take).
This did not happen before the latest patch (playing my second playthrough after patch came out).
Side-note: I find it very silly that the game does not persist the choices I had made previously and use those choices as the default ones in subsequent rests.
they actually do stay as what you chose, as long as you don't hit the prepare spells option after your long rest. i've noticed the same bug. each time you hit prepare spells, it resets them to whatever the game decides would be default.