C3D IFC export color issues

[kovacsv1]

When exporting block reference from C3D to IFC 4/4x1 using ifcexport command and the block contains solids on multiple layers (all solid colors set to bylayer), all colors are overwritten with the blockreference layer color in the IFC, thus making the entire block reference to appear in one color in Navisworks.

Using the ifcexportinfra command (set to IFC 4) the colors are as they should be.

Is this C3D issue or is there any options for this in Navisworks? I tried Legacy and Modern import as well.

I guess the two commands use different IFC classes for block references, but the ifcexportinfra is not in final state and is complicated to configure, so it would be best if ifcexport command worked.

Thanks for any ideas.