I am facing the same issue. I updated my Intel GPU drivers but the issue still persists. This started after the latest update. These Green Bars in the After Effects Preview panel appears every time. Some post on Reditt suggested unchecking "Enable Mercury Trnasmit'. Even after doing that, there is no change.
Abhi - I had same issues with intel drivers. I was able to solve this by removing my Intel drivers and let the Device Driver panel of Windows choose a default drive - that is Microsoft Basic Display Adapter. That worked for me. Intel drivers are having issues with latest AE updates. Instead choosing basic Microsoft Display Drivers solved my problem and get rid off these Green Bars.