This may be peculiar to my setup, but thought I would share. I use ServoCAT, Nexus DSC, and Sky Safari on a Galaxy S2 Android tablet. The DSC and ServoCAT require a reference staring point for alignment of North-facing, 90 degrees (straight up). This must occur before I can do the two-star Sky Safari alignment. I've noticed that sometimes when Sky Safari is connected (after the initial position alignment) Sky Safari shows the telescope as pointing at or near the horizon (instead of the actual position of the scope, pointing at Zenith.) When this occurs, the movement of the scope's encoders (as shown by Sky Safari) is shown as the exact opposite of the actual movement. It finally occurred to me what the issue might be and testing has proven this: If the scope is on a surface that tilts slightly to the South, pointing the scope at what appears to be the Zenith is actually past the Zenith and pointing slightly south. This, for whatever reason, causes the software to mis-report the scope position and axis direction. I'm adding a bubble level to my scope to prevent this in the future.
ServoCAT | If Scope Sits On Surface Tilted Slightly South, Pointing Scope At (What Appears To Be) The Zenith, It Is Actually Past The Zenith, Pointing Slightly South, Causes SkySafari To Mis-Report Scope Position And Axis Direction