State Covariance in tracking IMM

I have extracted state Covariance from a track filter and used it to construct a new IMM filter. But after assigning the values the filter's state covariance changes.

a = getTrackFilterProperties(obj,track.TrackID,'TrackingFilters','ModelConversionFcn','TransitionProbabilities',...
    'ModelProbabilities','State','StateCovariance','MeasurementNoise','HasMeasurementWrapping','MaxNumSmoothingSteps',...
    'EnableSmoothing','MaxNumOOSMSteps');
filter = trackingIMM('State',a{5},'StateCovariance',a{6},...
    'TransitionProbabilities',a{3},'TrackingFilters',a{1},...
    'ModelConversionFcn',a{2},'ModelProbabilities',a{4},'MeasurementNoise',a{7});

The results I get are these:

filter.StateCovariance == a{6}

ans =

6×6 logical array

1 0 1 1 1 1

0 1 0 1 1 1

1 0 1 1 1 1

1 1 1 1 1 1

1 1 1 1 0 1

1 1 1 1 1 1

For a side-by-side comparison:

[filter.StateCovariance,a{6}]