After engraving and cutting on my MK2, the image overlay stays on screen, and the workspace grid doesn’t come back.
I may not be following but I believe what you’re describing is how it should work.
The overlay will remain in place until you update again, restart LightBurn, or disable “Show” in the Camera Control window.
The update 15.02 took care of the work surface disappearing when finished with the burn issue.