@Olaf-Gottschalk I do not think this is a huge problem, you may not have had a complete sync with the watch when you first looked at the app. It almost always does work in the background. The data are not “wrong” as your watch may have thought that you had woken up earlier, perhaps you were moving around in your sleep.
Personally, I would take all of these metrics cautiously. If you are planning training based on what your watch is telling you IMHO you are entirely misguided. It is fine to use the information to help guide you but I believe nothing is better than your body and brain at making decisions regarding sleep, restfulness and your ability to exercise.