I'm having this problem. With no predictable pattern, when I use a media-key flirc floods my system with Vol up/down/mute (depending on what I was trying to do) for about 30 seconds. The OS UI becomes partially non-responsive during this period as well. Not sure if it the GUI or firmware. The Flirc is basically unusable as it will drive the audio to MAX at uncontrollable on seemingly random attempts to change volume. I can usually get a few buttons in before it goes nuts. Play/Stop have trouble as well, but not the arrow/enter keys.
Changing InterKey delay seems to make no noticable difference.
When I tried mapping a couple remote buttons to "keyboard" keys and "typed" into a txt window I got fairly consistent output, but occassionally it would put out a few extra letters, but never a 30 second UI hanging episode. InterKey delay didn't seem to make much of a difference.
Ubuntu 12.04 LTS, Flirc binary 1.2.7.rc.9, firmware 3.0. Denon RC-169 remote.
Was unable to install using Repo: apt-get install flirc ... "flirc depends: libfontconfig1 (>= 2.9.0) but 2.8.0-3ubuntu9.1 is to be installed" so I went here
In case it takes a while to get a reply... I'm next likely to try this again with a different remote, then with Ubuntu 14.04.