I found a function of HAdapt (named CopyLinXForm) did not copy a vector for semi-tied covariance to a new output transform. We should add these operations if (xf->vFloor != NULL) { nxf->vFloor = CreateSVector(x,VectorSize(xf->vFloor)); CopyVector(xf->vFloor,nxf->vFloor); } else nxf->vFloor = NULL; to somewhere in the CopyLinXForm function.