Interesting!!
Does the band of discoloration go all the way round the blank Eamonn? If so then that would almost certainly rule out fading caused by partial differential exposure to light which would likely only have affected one side.
If it is only on one side however, then that does not rule out the other suggestions. If it has delaminated then Buckeye's suggested methods should prove or disprove that, otherwise it may just be that part of one layer of CA was not fully hardened before later layers were applied and has subsequently dried in anaerobic conditions under the surface where it has gone cloudy for reasons similar to those explained by Neil here:
http://www.penturners.co.uk/turning-pens/4429-using-ca-glue-finish-oak.html#post61223