The Mets believe they’ve pinpointed the root of Harvey’s issues — a mechanical flaw that flares up as he pitches deeper into games. What’s also clear is that batters are slashing .241/.292/.373 the first time they face Harvey, .301/.326/.518 the second time and .509/.563/.764 the third. So if Harvey corrects the flaw and those trends persist, the Mets may want to investigate his struggles more deeply.