This issue is related to the fact that Microstation uses User, Site or system variables to load the individual fonts, they are not embedded into the file. For instance, if I open a DGN with Microstation that doesn’t have the client specific user interface the Font’s wont’ be correct. or the custom linetypes. This is can prove to be a problem even in Microstation alone. We have had success using Bentley View to view DGN files but we had to figure out how to edit the User workspace to load the client specific symbol files. If you only have a single client, you could figure out how to edit that in Bentley View and make that your default viewer for DGN files.