Update: YouTube 2FA Sign-In Bug on Chromium Fixed on XU4/Ubuntu18.04
The most recent update for Chromium on Ubuntu 18.04.1 LTS on the 4.14.73-149 kernel on the XU4 fixed an annoying bug for those of us who use YouTube with 2-factor authentication on the XU4.
Although the update stated it was a "security update", it fixed a problem that would lock up Chromium during the authentication phase of the login.
Unfortunately, Firefox still won't play YouTube videos whether logged in or not. After trying to buffer the video, Firefox simply responds with "An error occurred. Please try again later." Along with a Playback ID.