Seems that there are some adjustments required for the concept “Spatial Decomposition” in the published schemas.
There is a note on this page:
NOTE The link between the project and the highest level spatial element is provided by this concept through IfcRelContainedInSpatialStructure and not through declaration using IfcRelDeclares. This is a known anomaly intruduced to maintain compatibility with earlier versions of this standard.
Aside from the typo for “intruduced” it mentions the relationship IfcRelContainedInSpatialStructure that can’t be related to a project (only an IfcSpatialElement). It also seems to me that the concept is nominating the name attribute to be involved which seems incorrect.