I found that after starting the new launcher, allowing it to start downloading an update, and closing it, the launcher remains running in the background. After I closed the launcher, the game opened several minutes later, seemingly out of nowhere.
Expected behavior: Launcher terminates update process and closes gracefully.
Actual behavior: Launcher continues running in the background until the update completes and the game launches.
Sorry about the duplicate. I couldn't find anything when searching for the issue. Thanks!