[CLIENT] Executing lol.launcher.exe closes existing client instance w/o prompt

I was in champ select earlier when I accidentally clicked a shortcut for lol.launcher.exe pinned to my taskbar. It closed my already running client instance while I was in champ select without any prompts or warnings and opened the launcher. Queue penalties were applied, so I think this could be an issue for some users.

Steps to repro: join champ select in (I assume) any mode > execute lol.client.exe

Repro'd multiple times in custom games on my main machine running Windows 10 and on my other machine running Ubuntu 16.04. Not sure if this is intended behavior but I think it's an issue either way.