Relevant code in Picking.inl
If a raycast is completed immediately (thus RaycastPickingFunctor::operator() is run only once) m_result.previousVoxel is return uninitialized, with no way to check if it has been initialized. A boolean similar to PickResult::didHit (PickResult::hasPrevHit?) would rectify this issue.
note: The version is actually the most recent commit, I wasn't sure how to clear the version field after I accidently clicked it though