Utility Bay CoM not center

[jarmund]

After some observations during my reentries I needed to do some tests and my suspicions were confirmed: The utility bays (at least the 1.25 and 2.5 meter ones) are not balanced properly.

My testrig, from top to bottom:

1. Parachute
   
2. Pod
   
3. Utility bay (closed, nothing in it)
   
4. Heat shield
   
5. Decoupler
   
6. Some sort of launch hardware just to get on a ballistic trajectory
   

No parts were rotated or offset during assembly.

(This setup was repeated for both 1.25m and 2.5 meter pod with utility bay, chute, and heat shield of matching size)

Test method:

1. Launch to suborbital trajectory, just to get slightly out of the atmosphere
   
2. Decouple near apoapsis
   
3. Turn SAS off
   
4. Observe orientation in relation to retrograde marker with navball set to surface mode
   
5. Repeat with the exact same setup except from utility bay
   

All tests without utility bay points to a balanced pod, as the assembly keeps pointing to retrograde.

All tests with utility bay makes the pod tilt slightly compared to the above.

I also, just for fun and profit, did a few of the tests while reentering at 4000+ m/s with the periapsis set to 30km, with the same result.

Is this intentional? Can someone confirm this behavior, or am I doing something stupid?