According to us, Chopin changed the initially written 
to 
in Atut, probably with an intention of leaving place for a subsequent crescendo. However, the correction turned out to be incomprehensible for the engraver of FE (→GE,EE), who preserved . Like in bar 16, the mark in Atut is written between the chords, which, according to us, does not mean that it should be applied from the 3rd beat of the bar, like it was reproduced in the majority of the editions.
Compare the passage in the sources»
category imprint: Graphic ambiguousness; Differences between sources; Corrections & alterations
issues: Inaccuracies in FE, Corrections in A, Errors resulting from corrections
notation: Verbal indications