# Emacsclient uses new instance, weird font

When I open Emacs normally (using runemacs.exe), everything appears fine, including the font. However, when I try opening a file in Emacs using the client, while getting the client to start the server itself (that is, using -a "", so e.g. emacsclientw.exe -a "" testfile), it uses a new Emacs instance (even if I've already got one open), and also a weird font (currently Sans Forgetica, but previously Minion before I deleted it). I can't find these fonts stored anywhere Emacs would obviously look (I searched both ~\.emacs.d and my Emacs installation C:\emacs), and as far as I can remember have only ever used them once or twice within Emacs a few months ago, when I happened to do M-: (set-frame-font "font-name" nil t) RET. The problem goes away when I restart the server within emacs by doing M-x server-force-delete then M-x server-start. What is happening here and how do I fix it?