Each filer has its own spare disks. So it's perfectly normal to see different spare counts for each filer.
However, why the partner filer still thinkgs that 1c.58 is FAILED although the owning filer (filerB) sees the disk as working is beyond me. Maybe a simple "disk fail" followed by "disk unfail" (in diag mode) on filerB can resolve that issue. Otherwise I would open a case with NetApp if it bothers you too much. But as long as the owning filer sees the disk as usable (and not the other way round) it's normally not a problem