Don't know if anyone has that problem, but when you boot up the game there's a chance you'll first see the English option, indicating that all read dialogue is reverted back to the "haven't read" state and all unlocked music became locked again. Though it didn't affect my progress in my saves. Also, whenever that happens you see the speaking character's portrait in the dialogue box in the current session. They don't appear in other times.
Can anyone look into it?