We have the same problem - light won’t build on static meshes that are part of a blueprint with spot and point lights.
We use blueprint method to assemble a floor lamp inside of a blueprint class (where we also offset the pivot point of the lamp since the room we try to lit is cylindrical) and then use that blueprint (with all the lights and static meshes set up) in other places on the level to effectively make another copy of the same lamp, without having to redo its assembly setup again.
We do get the ‘‘x unbuild objects’’ message after a fresh light build and during gameplay the lights from those blueprints seem to be treated as dynamic, since the performance drops drastically when those blueprint lamp ‘‘prefabs’’ are used on the level.
DumpUnbuiltLightIteractions returns:
Lights with unbuilt interactions: 0
Primitives with unbuilt interactions: 0
We double checked that all the lights and static meshes inside of that lamp blueprint are set to Static. Moreover, the blueprint lamp has a Scene component as the root, with the Static Meshes, Spot Lights and Point Lights attached to the Scene component.
Any help/suggested workarounds would be helpful.
Thanks in advance!