Can you provide more detailed steps to reproduce this, for example what you change and to which font, any font mapping you have in place etc. Without these details it is difficult to provide any feedback.
1) I right click on a symbol and select Edit Local Symbol.
2) I select the port names (for this particular part IN, GND, and RESET) and change the font from Fixed to Sans Serif. Each port name has reflected the change in font.
3) I save the local symbol and then close it and return back to the schematic and notice that the port names have not changed font type.
I tried more than just Sans Serif and none seem to work.
It seems to me this is the completely two different thing, two different "editors" ???
Font used in Viewdraw has nothing to do with font used in Symbol Editor. They link together by name, not by font type.