Not seen this happen, but you could try another HDMI cable.
I doubt it's anything serious, but you could also try turning the box off for a few minutes and trying again.
Unless the box itself is showing any signs of failing such as recordings not playing, I wouldn't suggest any other resets at this stage.
Please remember to mark Solved Posts with Best Answer. Doing so helps other customers and saves TalkTalk's Support Team time by only looking at unsolved topics. Thanks, Steve (a fellow customer).
