Given a Movable Light with a Movable Mesh with enabled Self Shadow Only, the mesh will not cast inset shadows (despite this option begin forced to true according to Tooltip) unless the mesh is selected in the editor.
Right Mesh - Insert Shadows, Left Mesh - Self-Shadow Only:
Also reproduced in the following builds:
RESULTS: When Selected Inset Shadows are rendered, when not selected Inset Shadows are not rendered.
EXPECTED: Inset Shadows should always be rendered.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-17370 in the post.