Drastically wrong results when stop time of dataset provided is changed

[ap1510]

When we change stop time of spiral stairs dataset from 47 to 40, the plot generated is entirely wrong. Position in z-direction turns negative while it is positive and shows steps when stop time is 47. Steps in the initial time ( from 5 to 40 sec) should not change at all but that is not the case. The length of the step in the initial period changes and z of even the initial period becomes negative. Can you tell me, what's going wrong?
I have attached the screenshots for both the cases.

[FoilBorne]

I've discovered this too. I could be wrong, but I suspect it comes down to the stationary period at the end of each footstep when the raw data is used to recalibrate the drift. Changing this (or the input data if it does not allow the sensor to be stationary at the end of every second) will lead to this kind of nonsensical drift