I don't think it will cause a problem. When I see duplicate fonts a check usually shows that they are in different folders or in the same folder but the font names are a bit different. You can see the font names and locations in the status bar at the bottom of the window by hovering the cursor over a font on the list. That info will also be printed but I've discovered that it only prints each different file name once, then ignores duplicates.

For exapmle I have 5 instances of Andrade Swash, all just alike (I double clicked to open each and compared to make sure they all had the same character sets and apparence).

ANDRADE SWASH.TTF   c:\fontstorage\Initials\
ANDRADE SWASH.TTF   c:\fontstorage\Script\Elegant\
ANDRADE_SWASH.TTF   c:\fontstorage\Ornate\
ANDRADESWASH.TTF   c:\fontstorage\Ornate\Initials\
ANDRADESWASH.TTF   c:\fontstorage\Ornate\

Notice there are 3 different names (with a space, with an underscore, no space), in 4 different locations. The 2 in the Ornate folder have different names.

Obviously I need to clean up my font files.

But it is a pretty font...

Jill