External screen display loose colours by hdmi cable, got new macbook pro

Hi, I got new macbook pro bought 3 weeks ago, but got a problem with hdmi port. When i connect external tv/monitor its ok at the beggining but after 5-10-15 minutes(there is no pattern) it suddenly goes black for a sec and then it looses all colours and looks like "negative' photo? Something like blueish only etc. I have to move cable a bit or disconnect and connect it again. Then its back for few minutes. I checked 3 hdmi cables, tv and monitor ports are ok as i was using it on diffrent laptop. I tried not to touch laptop or cable but stil it occured. Even when it passes 15 minutes sooner or later it looses colours. And sometimes it looses it for like 1 minute and then by itself it comes back to normal

I used only chat help and they checked software, some standard things to check but everything is fine. Laptop is not even 3 weeks old. I have already made an appointment also for Genius Bar for next Sunday but wondering maybe some of you had similar problems. In genius Bar will they replace the laptop or somehow fix it right away without taking my macbook for few days also?

Thx for all the help, in attachement i am sending the photo of what happens when there is external monitor connected by hdmi port

Cheers,