Touch screen issue - help please

[scorpion]

Hi, I am a new member. I have a three-year old Karoq, which I love. But recently the touch screen has a lag on it before it activates, e.g. when I start the engine there is only a blank screen and after about 10 minutes it comes on and I can use it as normal. It's so annoying, especially if I want to use satnav. I've no idea why this is. Does anyone have any ideas why this occurs? Many thanks in advance.