When displaying an MX model using an MX Style set (i.e. MXRoad.pss) the colors aren't displaying as expected.
The reason is due to the colour table in the DGN file not being set to the MXRoad color table, the main cause of this is the DGN file being created using a non MXRoad seed file.
The example below shows the difference between a seed file that uses the MXRoad color table and a seed file that uses the Microstation color table.
Create the new drawing file using an MXRoad seed file (mx_seed_m_3d+2d.dgn) and the model will display correctly.