I have a couple of devices that appear unable to see my router's WiFi signal when its put up on channel 12, 13, or 14. Some newer devices work fine without any problems. Others cannot see the signal. I can confirm the non-working devices can't see my wireless signal at all -- If I use inSSIDer and look at the "2.4 GHz channels" tab which shows the channel layout of my WiFi channel vs my neighbours', channels 12-14 will show nothing on the non-working devices while the working devices show my WiFi signal nice and strong.
When searching on Google "WiFi channels 12-14" I've also noticed several posts about channels 12-14 not working for certain people another post about 12-14 being added to newer versions of android.
My suspicion is that channels 12-14 were added in 802.11n but some of 802.11n draft devices don't support those channels. If that's the case, however, I'm surprised that my router would even choose these channels during auto selection since I set it to be compatible with 802.11b/g/n devices.