Sleep Entry Showing up on Wrong Date
When metadata points (sleep, exercise, etc.) are added, it records it to your log (Previous Logs list) regardless of whether you enter it on the reading or separately. It is based on the start time so it'll show up today if it started after midnight, yesterday if it started before midnight.
When you're doing morning readiness, it defaults the sleep to last night and the exercise to yesterday, but you can manually adjust the dates-times if needed when you enter it, (or later) for sleep when you adjust duration, it adjusts the start time and leaves the end time (because you likely just woke up).