Simulink simulation stops due to unknown reason

The simulation runs smoothly until adding the following to ADCS_Tracking/ADCS/Ideal control/Tracking control:

u_satmax = cross(w, I.*w) - K1*I.*(w - 0.45*pi/180/sqrt(3)*ones(3,1));
u_satmin = cross(w, I.*w) - K1*I.*(w + 0.45*pi/180/sqrt(3)*ones(3,1));

for i = 1:3
    if u(i)*w(i) > 0 && abs(w(i)) > 0.4*pi/180/sqrt(3)
        if  w(i) > 0
            u(i) = u_satmax(i);
        else
            u(i) = u_satmin(i);
        end
    end
end

From that point on, the simulation stops, sometimes prompting the consecutives zero crossings error (not always). This is fixed when suppressing either the ADCS_Tracking/ADCS/Gyro or the ADCS_Tracking/ADCS/Real control/MT subsystems, but I cannot find the error in either of the two.