If you are using notation versions (instrument name is preceded with n-) of an instrument use CC68 instead of CC64 for legato on winds, brass, and strings when the instrument does NOT have 'auto legato' enabled.  If you are using the standard version then CC64 engages legato for these families of instruments.  If auto-legato is enabled, then the cross-fade legato effect is caused by overlapping notes, but then the instrument can only be 'monophonic' (one note at the time).  In these type instruments there is no 'sustain' pedal.  If you really need a sustain CC it's possible to add it in the SFZ file, but it's not there out of the box.

Keyboards/pianos/organs use the standard CC64 for sustain.