Launcher workDir argument not working

The Launcher --workDir argument seems broken.

When I download the Other Linux tarball (https://launcher.mojang.com/download/Minecraft.tar.gz)  and run

./minecraft-launcher --workDir /home/merlijn/testminecraft/.minecraft

Minecraft downloads the files Launcher to /home/merlijn/testminecraft/.minecraft but then tries to execute a non-existent launcher in /home/merlijn/.minecraft.

I attached four logs:

• minecraft-launcher-cli-log.log is what I see in my terminal after running the above command.
• I found launcher_log.txt and launcher_subprocess_log.txt in /home/merlijn/.minecraft
• I found launcher_subprocess_log.txt in /home/merlijn/textminecraft/.minecraft

From the CLI log, it seems as if the minecraft launcher gets executed multiple times. The first time, it correctly used workDir, but the second time, it seems to forget that parameter.