A common problem that we see when using some positional servos is that the servo housing can shift if the servo tries to move beyond it's normal range. When this occurs, the HoverflyGIMBAL will read unusually high or low Center Point values for the effected servo (above 1.6 or below 1.4). This is most commonly seen on the tilt servo, but can appear on the roll servo as well.
To correct this, connect to the HoverflyGIMBAL Setup Client. Go to Configuration & Calibration > Servo Configuration and select the effected servo from the drop-down menu. Then simply hold the camera tray in place with your hand while adjusting the Center Point to 1.5 or something close to it. The servo's movement will force the housing back to its' proper alignment.