Of course...
You will always level your head with gravity, unless you lean back on purpose.
It’s a limitation of the viewing reference system of the sim. The VR reference system only picks up the angle of your head, not your torso. So if it aligns the view with the horizon, when on ground, you’d be looking down, when in flight.
Try leaning back, when sitting on ground and hit re-center. Now sit up normally. Your view should be aligned with the horizon. After you take off, hit re-center again to align with the aircraft.