I'm an old user, having happily installed Flirc with the 1.0 firmware on my Raspberry box running Openelec...
Recently, noise creating phantom-keypresses lead me to a thread where it suggested updating the firmware, which now provides a noise control.
I did it, but I couldnt check yet if the noise issue is gone, because now it appeared the one-keypress-every-two issue. It certainly is firmware related, because nothing else changed.
I tried the procedure to record twice every key, but it didnt solve the issue.
For additional info, I attached the output of flirc-util settings