Here's mine.... :)
Dear customer,
Thank you for your message and I appreciate your patience on this matter.
Reality is, ensure the clients are running the latest version of our software. For Mac, the 2016 version of KIS was released a couple weeks ago and for Windows, 16.0.1.445 is out and available for download.
With double-key strokes, the issue is Trusteer and the work-around is to disable Trusteer's Character Displacement".
If issues persist, traces would be required and of course we would need a specific client to focus on and be in constant contact with for the required diagnostics and troubleshooting.
Looking forward to your reply.