I just want to know why in same minute and same second my coins transferred to unknown address
Since you are sure that it ain't your change address, that is why I think the Electrum you downloaded may be "fake".
Fake client, either change your output address, or fake the change address.
Do you still have the original setup/portable exe file? If you want to, you can upload to
https://uploadfiles.io and we can check the authenticity for you, if you don't want to check it yourself.