Inspector can't be "the" cause of damages resulting from negligent construction

In Smylie v. Dryden Construction, Inc, et al., the Court of Appeals dismissed a case against the township building inspector arising out of defective construction.  The plaintiffs argued that the home they purchased was built over "natural underground watercourse" and that the inspector's failure to consult drain commission maps was the primary cause of their problems.  The Court of Appeals held that even though there was evidence of "gross negligence" by the inspector, he was immune from responsibility because his inspection responsibilities--when compared with the actions of the builder--could not qualify as "the one most immediate, efficient, and direct cause preceding an injury."  The latter is the formulation of "the" proximate cause requirement devised by the Engler Majority when it held that a government actor should not be jointly responsible for damages caused by multiple actors.