PDF Export with a custom font giving the error "Cannont find or create the font 'xyz,Bold'."

I've ran into an issue I have never seen before, maybe somebody could help before I pull my hair out any more. We've got some reports we did for a customer in SSRS. They work fine and render fine. Recently the customer gave us a custom font their company uses, and wanted the reports to use that font. I installed it for all users on the server, and updated the RDL files. The problem is that they gave us a single OTF file for the font to use, we'll call it "XYZ". Now when I try to export the report to PDF, which is their ultimate end result, I get this error in Acrobat when I open it:

"Cannot find or create the font 'XYZ,Bold'. Some characters may not display or print correctly"

I have no idea how to fix this, the client has led me to believe there isn't a seperate Bold font file, but maybe there should be? I know if I recreate the bold font in Acrobat it works perfectly, so I think that is fine. Also the report renders in the browser with the correct font, and same with the Word export. Just hoping that maybe there is something in the device info or settings that I need to switch to make this work? Or that somebody can guide me in the right direction?