Found the problem: During troubleshooting I had turned off keyboard repetition in System -> Keyboard -> General, since when this bug was present, I would get double characters (probably because the delay got set to zero). For my test user which hadn't messed around with the settings, it worked again after the upgrade without any adjustments.
Found the problem: During troubleshooting I had turned off keyboard repetition in System -> Keyboard -> General, since when this bug was present, I would get double characters (probably because the delay got set to zero). For my test user which hadn't messed around with the settings, it worked again after the upgrade without any adjustments.