ctrl keys interference with wifi

eventhough Keyboard-navigation is OFF, it appears that working on my laptop, with iTunes operating in the background, using keys like SHIFT and CTRL interfere massively with the Bluetooth-broadcast, causing music not to be streamed smoothly. So typing becomes a frustration when iTnes is ON.

Is this a known issue?

Any solutions for this?

What I tried so far:

-change of WiFi-channel

-restart computer

-restart Bluetooth-connection

no positive effect found.