Why does font substitution appear to happen when exporting a board into a PDF?

[Yannig]

I have a situation. I export an entire board into a PDF, but for some reason the letter Q is changed into the letter Z in the PDF. If I browse the board, I still clearly see the letter Q, but searching for it, does not find it. It seems like a font substitution under the covers?

So if I search for Lasquez, I cannot find it. If I search for LasZuez, I find it! If I export only the card, I can see the Q fine. If I export the whole board, the behavior above occurs. 

This is a problem, because searching for names becomes unreliable. 

Any ideas?