Please do not perform an alignment reset during the initialization phase of the filter. For the MTw the initialization phase can last several minutes depending on the magnetic environment.
If you perfrom a alignment reset you would expect the filter to take the new value as fixed "North". However, this does not work like that in the current Kalman filter that we have. You can use the alignment reset only after the heading has stabilized. It is recommended to wait at least 5 minutes before you perform the alignment reset.