According to us, the mark written by Chopin in FEcor is a long accent, same as in analogous bar 17. An unequivocal long accent is also in Ap. In FE (→GE1→GE2) the mark was interpreted as 
hairpins, which, in this case, cannot be considered as an inaccuracy. In EE2 and GE3 (→GE4→GE5) the sign was omitted, whereas in EE3 (→EE4) a long (!?) accent was added.
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources
issues: Long accents, EE revisions, Errors in EE, Errors in GE
notation: Articulation, Accents, Hairpins
