I got stuck with a bug in Sandpoint Cathedral that seems basically to be the same as the mending bug.
I then went to "Story" on the main screen and it showed me my current party (Kyra + Merisiel) and said I could create a new party. I chose "Experienced" Merisiel to see what would happen (would locations still be unlocked? Would I still have my deck?). I saw that it looked like I might be able to create a fresh party with Merisiel and Kyra and continue, so I hit "quit".
Then I hit "Story" again, and it still showed me just the one current party (Kyra + Merisiel) and new party option. So I decided to create a party with experienced Kyra + Merisiel. But now Experienced Merisiel showed as "locked". She is technically in a party, but so is Kyra, and previously I was able to create a party with experienced Merisiel. Also, the text implies I can.
So somehow I got Merisiel locked up so I can't continue with her.
(Minor note: If I add Kyra to the party, the Merisiel "unlock" icon vanishes, but I still can't add her. As soon as I click to "new" and back to "experienced" the lock icon reappears - so this looks like a UI refresh/update issue)