The optimization view mode 'Quad Overdraw' image is not properly cleaned up when switching directly to 'Stationary Light Overlap' view mode. See attached images.
Result: Lines on screen from Quad Overdraw remain visible even though viewmode has been changed to Stationary Light Overlap mode. The lines are transparent and superimposed over the viewport but remain static relative to camera position.
Expected: Stationary Light Overlap viewmode would appear without the lines from Quad Overdraw.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-54580 in the post.