I've rough turned a few bowls and finished some of them pretty nicely. The bowls are not that large (about 10" or 11") and I let them dry for about 5 months. After rough turning, I applied end grain sealer ONLY to the OUTSIDE of the bowl on the end grains. The bowls did not crack during drying ... however after finishing them, I've noticed a few small cracks on the end grain INSIDE the bowl (see pic). I can't see any on the outside.
Did I not let them dry long enough? Is there something else I've done wrong during the process?