“Self Shadow Only” flag working only for dynamic shadows, for baked shadows it’s not wokring.
The self shadowing of the object AND the objects shadow onto the ground are handled by the same Per-object shadow, which is applied in a deferred pass to any pixels in the area. That means it is harder to separate what is self-shadowing vs shadowing on other things. It requires knowing what object each pixel belongs to.
It’s still possible to do, just not in the way without some serious codingt. The high level is to setup a stencil mask on the character’s pixels to mask it out during the Per-object shadow projection pass. This would be done in FProjectedShadowInfo::RenderProjection.