the short answer:The biggest problem with IFC is that vendors often don't stick strictly to the schema when exporting their objects, they often just export the bare essentials of information rather than getting down into the nitty gritty of the schema.
For example, when importing a 3D solid universal beam ('H' beam), if the profile exported is described as "310UB40" and the application importing the schema uses a matching profile but describes it as "UB31040" you usually have to write a mapping file so it knows how to draw the beam.
That is, Bricscad can't draw missing info if it's not exported, each application uses the schema differently.
The longer version:This is ridiculous!
The schema caters for the primitive profile geometry but it is too specific and it's a lot of work to create the geometry routines to cater for every type, have a dig around in here for an idea on the complexity that is IFC ->
https://standards.buildingsmart.org/IFC/DEV/IFC4_2/FINAL/HTML/That is at the profile level and it goes much deeper!
What they should have done is have very primitive geometries such as points, lines, polylines and compositions of these and use these to store the primitive geometry that any CAD platform draws easily. All other data is just that, data!
What this means is that any CAD platform can at the very least draw the 3d solid, it doesn't matter what it's called really as long as the rendered object is true.
BIM is a wonderful thing but it's a beast to implement using IFC. Until all vendors validate their data against the schema on export and import will the data be true and correct.
end rant
Then again, it may just be a bug, let BricsCAD know and they might be able to help. BricsCAD support is very helpful and usually get back very quickly considering.