What strategy should be employed if a Patent Examiner incorrectly marks an office action as "Final"?

It is better to call the Examiner and request that a new office action be sent marked "Non-Final."  If the Examiner refuses, phoning the Supervisory Patent Examiner is usually the next best play.

Although it is possible for you to submit a written request, the request may take a month or longer to be processed -- and that assumes your request is even processed at all (many of these written requests routinely go ignored).  For this reason, it tends to be much safer to call, rather than write.