This seems like a serious issue, so many people have reported it, however the problem had only happened to a random few with no clear pattern as to the issue/cause, especially as it was not reproducible by any of the LWJGL devs.
After discussing this issue on irc, our resident genius MatthiasM had the theory that it might be ibus that causes this problem.
Funny thing is that over at jME3 we were having this issue for months. Will be interesting to see where this goes ..
Interestingly after some googling, there was a possible solution/cause found on the
jMonkeyEngine forum here I reckon the next move should be to try to get ibus to work with LWJGL instead of disabling it. Any idea's on how to proceed or support ibus?