Default [Q] Power button disconnects call even when unticked in Settings.

Does anyone have any idea how to stop my F400S G3 on the latest firmware from disconnecting a call with the power button.
I want it to just turn off my screen.
I have tried both the check box under Calls and Accessibility but no matter if it's ticked or unticked it always ends my call and I don't want it to.

I hope someone can help me as I've had no luck so far.