I know this topic is ancient history, but if anyone is still having problems with their remote, I was finally able to fix mine.
I ran across some settings in advancedsettings.xml that pertain to remote key press delay and repeat. The following is from the Kodi wiki:
2.10 Input control settings
The repeat delay for a LIRC remote control. A delay value between 1 and
20 before a remote button starts repeating on a long keypress (i.e.
continuously sending button pushes while it's held down).
This used to adjust the amount of time in milliseconds between repeated
keystrokes. Used to prevent key-bounce, in other words prevents Kodi
(lirc?) seeing one key press as multiple key presses with certain
I tried leaving the Remote Delay value at the default of 3, and using the suggested 800ms value for Remote Repeat, and my remote has stopped performing multiple key presses with a single button push. Really wish I'd stumbled across this a year ago!
The advancedsettings.xml file belongs in the profile directory on Slice, so create it using the guide on the wiki and then use System/File Explorer on Kodi to copy it from your PC into the Profile directory on Slice.
Ironically, I came across that wiki while looking for ways to increase the video cache for my Fire TV box since it was stuttering a lot on local files. Now both my Kodi boxes work like champs