[macOS/XQuartz] Launched application has wrong X11 `DISPLAY`, making application fail to launch

I can launch applications from the terminal just fine, and I can launch xfce4-appfinder itself just fine, but when I try to launch any application from xfce4-appfinder, it fails to launch:

(mousepad:19599): Gtk-WARNING **: 20:37:26.881: cannot open display: /private/tmp/com.apple.launchd.bQzI8WuvLg/org.xquartz:0.0

The proper display variable:

qwerty@macbook:~$ launchctl getenv DISPLAY
/private/tmp/com.apple.launchd.bQzI8WuvLg/org.xquartz:0
qwerty@macbook:~$ echo $DISPLAY
/private/tmp/com.apple.launchd.bQzI8WuvLg/org.xquartz:0

Oddly enough when I run echo $DISPLAY directly from xfce4-appfinder, the value is correct:

/private/tmp/com.apple.launchd.bQzI8WuvLg/org.xquartz:0

It seems when running a normal application, an extra .0 is getting added on to $DISPLAY somehow. Issue exists with both 4.18.1 and 4.19.2. I'm happy to help debug, just need a pointer on what direction to look in.