Broken interaction between lunar blessing moon beams and combo buildup

Lunar blessing itself is not supportable by combo support gems. However, the lunar blessing beams are marked as supportable by gems like culmination. When I slot culmination in to lunar blessing, though, nothing happens. No combo meter appears and the damage for the moon beams doesn't change when I attempt to build combo. Either this is a bug that the moon beams are supportable by combo skills or the damage numbers are broken or it is just a broken interaction.