Current Residence: Israel
Favourite genre of music: Rock and Metal, Movie Soundtracks, Classical
Operating System: Windows 10 Pro 64bit
MP3 player of choice: Hard: Samsung Galaxy S9+ / Soft: MusicBee
Wallpaper of choice: Wallpaper Engine
If I understand you correctly than that looks like a Rainmeter application bug and not a skin specific problem.
I suggest that you post this issue in the Rainmeter forums:
Might be something to do with Windows 7 text encoding. I have no idea to be honest.
That symbol is a Unicode symbol called Black Droplet. it is not a part of the Century Gothic font.