The action should be, and have always been in Unigraphics / NX, that if the used font is unavailable , NX uses Blockfont instead.
The Problem with this is that way-way back in time, Unigraphics only used ASCII for the input. ASCII is only 127 (?) characters which led to that in other languages we had to use odd methods to map local characters in local fonts. "$|" was mapped to "ö" and similar. Those characters was of course lost when UG swapped to Blockfont.
The use of True type Fonts should be the more future proof way.
Regards,
Tomas