The Android 10 One UI 2.0 beta for the Galaxy S10 series has a critical bug: The device is locking people out by refusing to accept their PIN, password, or pattern, with the issue cropping up after a device is restarted. Those who have set up the Remote unlock feature enabled on their phone have been able to use Samsung's Find My Mobile service to delete all biometrics (password, PIN, pattern, fingerprint and facial recognition), but since the bug causes the device to reject all passwords as incorrect, they have been unable to set a new pattern/PIN/password afterwards.
Unfortunately, not everyone has Remote unlock enabled, and for them, a factory reset and flashing back to Android Pie via Samsung Smart Switch (which deletes all data) is the only solution. Some users have even been unable to set a pattern/PIN/password after reverting to Pie. Samsung is yet to officially say anything on the matter, and it's unclear how the company will fix the problem for those users who don't want to factory reset their device and are locked out. A regular software update won't cut it, as a device needs to be unlocked for installing updates.
Take precaution before the issue affects your Galaxy S10 or Note 10
For now, if you're using the Android 10 beta on a Galaxy S10 or Galaxy Note 10, it's recommended that you change your lock screen security method to swipe or none from the Settings » Lock screen menu until Samsung releases a new beta update or a fix for the problem. You should also enable Remote unlock from the Settings » Biometrics and security » Find My Mobile menu on your phone so you can use Find My Mobile to access it you run into the issue in the future.
We'll be keeping a close eye on the situation as it develops, and in the meantime, you can tell us if you have faced the issue on your Galaxy S10 or Galaxy Note 10.