I bought my 5-mode K-106 around 6 months ago and initially found that it would flicker and changed modes of it's own volition. I found that the pill was not fully tightened into the head of the torch, and so was not making good electrical contact. I tightened the pill up using a pair of small needle-nose pliers, and this overcame the problems.
More recently I came across this thread:
http://www.candlepowerforums.com/vb/showthread.php?t=258549
and found that my K-106 also suffered from the same problem - the circuit board was misaligned in the pill, and the solder joints were poor quality and appeared to be very close to failure. I carried out the resoldering described here and since then I have had no problem at all with the Akoray.