As we mentiond in our announcement of this new IFC importer, there is a temporary mechanism to trigger the old v2 IFC importer logic, if you name your files .legacyimporter.ifc before upload.
You may have more success with receiving this in v2 grasshopper connector.
However, the structure of the data from the v2 IFC importer is very different from the new v3 importer.
I should also mention that this option will not be available for very long. We promised to keep it active for 4 weeks, which has now been exceeded. We will likely remove the logic soon. But for this week, it may provide you with a temporary solution until we have a proper v3 grasshopper connector.