Welding a static mesh to a UGeometryCollectionComponenr

Hi,
I am trying to make a breakable actor that has some static meshes attached to it.
No matter what I do I can’t find a way to attach these meshes to the geometry collection: I tried AttachComonentToComponent with physics enabled / disabled, collision enabled / disabled in any combination. Tried with any attachment rule possible.
The results are almost the same: the geometry collection moves and the mesh is left behind. If physics and collisions are enabled it just moves around on it’s own.
What am I missing?

EDIT: I just noticed that the geometry collection location is not actually changing even though it’s moving. How’s that possible?