Issue
Some people reported loosen handlebar which is a big security issue and must be addressed properly.
Caused by
The existing screws that hold the handlebar barely bite into the actual stem and headset
Solution
It would be best to replace them with longer ones. Use M6 30mm or M6 25mm. For extra safety, you can use the thread-locking fluid or threadlocker for the screws.
The original screw in comparison with the longer one 
