It seems (alembic) geometry cache actors do not show up in reflections.
The materials on these actors can receive reflections, but the geometry cache actors themselves are not shown in reflective surfaces as shown below (the red and blue characters are alembic caches from Maya imported to UE4 as geometry cache actors, everything else in the scene are static mesh actors).
I’m pretty sure I’ve done everything right to get proper reflections, and I get them on/from other actors in the scene just fine.
Is this a bug or am I doing something wrong?