The traces of erasure visible in A reveal that Chopin initially inserted the 
mark under the bottom stave, more or less there where it is to be found in the editions. It can also be seen that the initial mark was longer, since it reached the first L.H. quaver. The corrected version of the mark was shortened and moved over the first chord. In this form, the mark is to be interpreted as a long accent, which we give in the main text. The engraver of GE (→FE1,EE) moved the mark, which he most certainly considered a diminuendo, under the stave, probably to avoid a contradiction with poco cresc. or simply due to lack of space over the stave (a hairpin on the stave is poorly visible; such a solution is applied only in exceptional cases).
The fact that the mark is absent in FESB is most probably due to an oversight, one of a few in this bar.
Compare the passage in the sources »
category imprint: Differences between sources; Corrections & alterations; Source & stylistic information
issues: Long accents, Corrections in A, GE revisions
notation: Articulation, Accents, Hairpins