The error was spotted during the tests. It is being worked on, but no solution could be found so far.

The problem occurs when you look at the “Statistics” page, then go to your profile and make a setting (for example, change the nutrition start or the nutrition preference).

The backup takes place only in a few conditions. Other data is not lost in the process.
The app runs stable again as soon as you restart it.

Since this error only occurs in this rather unlikely situation, it does not get a high priority.
Nevertheless, this error will be followed up.