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Would module wide caching be something to cause this? I'm not sure, but if you have your newwbb module cahed at any level it may create situations like this, but I wouldn't know for sure.
If you have the cache feature enabled for the module in your sytem admin preferences, then try it without any cache to see if that solves the problem.
If your not caching the module, then I don't know what else to say and differ to the rest of the community for an answer.