To clarify, lack of belief in the Bible as gods word?
If one has a crisis of faith that becomes known to the elders, they can still be a brother or sister in good standing if they don't violate the rules and they work on that lack-of-faith problem.
If one flat out states that the Bible is not the Word of God, then it lends itself to their condemnation. You cannot believe in the organization if the organization believes in the Bible and you deny it.
But even then, if you were willing to keep your problem to yourself, many elders would say "Work on that" or "Keep that to yourself."