I changed my password in valence (forgot password), went back to Roon and suddenly had to type in the new password - the whole history and statistics were gone away and set to zero.
Try restarting the core. Then, make sure that you have the same user profile selected that you had before. Nothing was actually deleted–it’s all still in your database.
I did all - rebooting the core, same profile, … the information about history and „statistics“ we’re gone also in the other profiles.
So I restored from a backup and decreased the interval.