Hi rclogg,
Welcome to the Heartland Owners Forum.
No, what you described is not normal. Manually retract the rear/center jacks on both sides and try auto level again. If it does the same thing, you should manually level the coach and then do a zero-calibration. See if that corrects the problem.
ZERO SETTING THE CONTROL
1. Turn “ON/OFF” button “OFF”
2. Push “FRONT” button 10 times,
3. Push “REAR” button 10 times
4. Control will flash and beep, LCD says “ZERO POINT CALIBRATE”
5. To memorize this level condition , press “ENTER”
6. LCD says “ZERO POINT STABILITY SUCCESSFULLY SET”
7. The control will then turn off.
8. Turn “ON/OFF” on to commence operation.
If you have ongoing problems, the rear sensor may have come loose from its mount. It's in the center, near the axles, either behind or possibly in front of the fresh tank. As pictured here, it's behind. If you remove a few of the coroplast mounting screws on one side, you should be able to peek inside and see how it looks.