it's one of the better quality books on wn. it has a few important informations missing or change subtly change through the chapters but they aren't glaring plot holes. (well one is but most won't really notice it)
I hope the author takes his time to plan and keep track of the important information to minimize the changes.
that said this is a general issue with books on wn because they aren't rewritten and edited for another year or two after the first version was finished. we most likely are reading the first written out version of it