Could you provide more details about the data source that you're using, and what behavior it has when opening it up in ArcMap or Pro? I just tried creating a shapefile with an explicit null geometry for one of the values, and it is correctly read into R, with any entries containing null references included (the equivalent of dropNULLGeometries=FALSE with rgdal). Further downstream transformations (like data2sp) may drop this null geometry as they don't have null geometries as part of their data model. If you can share some details, happy to dig further.
It is a point feature class from a file geodatabase. Its for a conference, so I should be able to post the data next week. I believe data2sp is what the 'issue' is. So, your statement makes sense on why it would be dropped.