No, a bug with these symptoms was fixed in b5 and shouldn't have returned in b6. Are you sure you're actually having the same issue? That is, does the same replay work fine with b5 and only fail with b4 and b6?
If not, then you're probably having an issue that is not the same as this one but has similar symptoms. In that case please open a new thread. Either way please provide more information (especially the full game log).