If moisture was the problem, 95% of the time, the CA would be cloudy in near the end.
That pict shows sand-through. I don't know your method of finish, but quite often, too often, people do not get as thick of a build up of CA as they think. It is NOT the number of layers that matter, it is the THICKNESS of the layers that are important to prevent sand-through. I do have experience and many here also have experience - I "can" add more thickness in two layers than some people put on in 8 - 10 layers. I rarely put more than 3 of my layers on and do not have sand-through. It is a matter of thickness build up.
Calipers help determine how much build up is there. Don't measure the diameter of the wood by the bushing. Measure with the calipers.