Did we encounter a fatal error while checking an inherent?
A fatal error is everything that fails while checking an inherent error, e.g. the inherent was not found, could not be decoded etc. Then there are cases where you not want the inherent check to fail, but report that there is an action required. For example a timestamp of a block is in the future, the timestamp is still correct, but it is required to verify the block at a later time again and then the inherent check will succeed.