Comment 6 for bug 1885474

I have the same issue. As mentioned in reddit thread in OP, the login screen displays properly at 1366x768. I'm running MATE so I'm not sure how to implement the workaround @johnnyl33-k mentions for Xubuntu since there are no reflection options. I will note setting rotation to 'upside-down' in Control Center->Monitor Preference does not suffer from the tearing the 'normal' rotation does. It's just hard to work upside down!