Custom Application Launcher Disappears

I have a custom launcher on mate-panel for Sublime Text editor, directory /home/USERNAME/Documents/sublime_text_3/sublime_text. I can create a launcher and it runs fine, but the next time the panel is restarted, for example running pkill mate-panel, the custom launcher disappears. If I make another custom launcher for Sublime, the original custom launcher suddenly reappears after it’s been added to the panel.

Edit: The same thing happens though after that, if the panel is killed, the next time it’s restarted there are no custom launchers on the panel.

Rebooting doesn’t cause any custom launchers to reappear.