Peak envelop function does not work in Simulink

The Peak Envelope function works well through the command window.

But when I try the exact equitation in Simulink, it just returns the input signal for both up and low envelope signals.

I also tried suggested models in:

https://www.mathworks.com/help/dsp/ug/envelope-detection.html

As you can see in following image the distortion at the beginning is not acceptable at all.

How can I implement precise Peak Envelope function in simulink?

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