Using latest stable Krypton 17.3. with an xbox one wireless controller
If inactive the pad turn itself off automatically after 15 minutes. It is by design, and it usually goes to sleep when watching a show/movie.
When waking up the controller manually to regain control over Kodi, the left and right triggers will always be unresponsive (all other buttons will work as expected). Only way to get the triggers to work again is to close and restart kodi.
Very easy to reproduce 100% of the time after the controller wakes up.
I believe it is linked to Kodi 17.x since Kodi 16 did not have this issue