The lines weights are incorrect in print / preview when using a MicroStation Pen Table to change the line weight.
The problem can be solved be changing the “Element symbology comparison mode” to “As displayed in view”.
To correct the problem:
MicroStation Pen Table is attached in the Print dialog box.
Go to -> Resymbolization -> Edit Pen Table -> Global Actions -> Pen Table Options ... -> "Element symbology comparison mode” change to As displayed in view