My book is a second printing of the core. I have had it about 6 months. It looks like pages are about to give way to have a middle section fall out. I've been thinking of buying another book, but a friend suggested I come on the board. I think if it is occurring to such a small portion I am fine with that. The way he described it I thought more people had problems. The $50 is not such a big deal to me, I don't need the stress.
Perhaps the third printing could try for 2 books for $25-30 each together as a set. Having a thinner binding seems like a good idea.
My book is breaking at pages 30/31 and 546/547.
However, I do find it interesting that someone else has a similar problem on these pages in a different printing.