Having keystroke issues with macOS Sierra on two different Macs I'm having a series of problem with my macOS Sierra 10.12.1 every once in a while after a random period of normal operation. The series of problems include:


My 3rd-party Chinese input methods (Sogou &amp; Rime) both start double-typing on every letter. English isn't affected, but cycling through the keyboards do not help with the problem.
Launchpad starts taking double keystroke and double touchpad swipes on arrow keys, basically skipping any odd-numbered pages
Any keystrokes plus the return key would launch an app whose name starts with those keystrokes (which is a Spotlight behavior) regardless of whether Spotlight is on. This problem is somewhat intermittent.
There are no apparent log traces (that I'm aware of) in the console.
All above problems begin together, and persist until restart.


I have cleared any keyboard-related config files in /Library and ~/Library, as well as purged all apps with access to accessibility function, but nothing would work. The problem has been observed on both the MacBook Pro 13" (2011) and MacBook Pro 15" 2016, with Touch Bar, which migrated the system from the former.

Anybody could give me a clue what could be happening?
A friend of mine, who works at an Apple Premium Reseller, told me that:


It's a known problem that has to do with MacOS Sierra;
Results in all different sorts of weird behaviour until reboot;
Only happens on factory installed Macs (running MacOS Sierra);
Is not harmful for your computer (hardware); and,
Advised to wait for a software update from Apple.