Why does the Magic Keyboard keep working when turn off

My keyboard without fingerprint (model A2450). When I turn off keyboard which mean is no green! it silver!

I immediately type something it will basically reconnect to macbook again.

Steps to reproduce (macbook + keyboard is already connected to this macbook)

1) turn off physical on keyboard switch it to off

2) immediately type something on keyboard

it will connect to macbook again.

I also see this happening with closing lid of macbook:

Steps to reproduce (macbook + keyboard is already connected to this macbook)

1) closing lid macbook

2) turn off keyboard

3) immediately typing something on keyboard

Result: you will hear that sound on macbook that it try typing something.

Macbook model macbook pro 14 2001

Keyboard model without finger print A2450

Also see happen with mouse A1657 with clicking.