ARIMA samae forecasts across horizons

Why is it that I get the same forecasts for all forecasting horizons in MATLAB?

Mdl = arima('Constant',1,'AR',{0.3});
Mdl.Variance = 1
[Y,E]=simulate(Mdl,20);
Mdl1=arima(1,0,0);
e=estimate(Mdl1,Y);
forecast(e,10)
ans =

    1.3642
    1.3642
    1.3642
    1.3642
    1.3642
    1.3642
    1.3642
    1.3642
    1.3642
    1.3642

[BN]

Dear @Shaoni Nandi, Did you find an answer? thanks