Those lines are zebra stripes, not a screen fault. They’re an exposure warning overlay shown in live view to mark areas that are very bright and may be overexposed.

On the G7, zebras usually indicate highlights reaching a chosen threshold, often around 100% (clipped white), though the warning level can be adjusted in the camera settings. In your example, a bright object like a laptop screen is much brighter than the rest of the scene, so the camera flags it.

Because zebras are only a display aid, they do not appear in the recorded image. If the final photo looks fine to you, nothing is wrong. If you want fewer warnings, you can lower exposure or change/disable the zebra setting in the camera menu.