Hi @annage, here's some details from the Oura support page, could any of it be the reason?
The Oura App might not import data from integrations if both apps were not opened before midnight, if "Background App Refresh" is disabled, or if "Lower Power Mode" is enabled. Open both Oura and the integrated app at least once a day to prevent this.
The Oura App will only sync activities for the current day. If you are having trouble syncing your activity, verify that "Date Added" matches the date on which the activity occurred.