Mark I consumes bandwith and affect navigation for other devices connected to WiLan

It is curious, but connect Mark I affects the navigation for other devices
Bandwidth for the rest of devices connected goes down.
E.g. I cannot open speed test, I turn off mark I and then navigation is better and speed test can be opened
Addtional comment, I am not running any operation on Mark I, just turn on device

Does anyone have this issue? Do you know what can be causing this?