In FE (→GE1→GE2), there is no accidental before the 4th demisemiquaver before last. The missing 
must be a mistake in this context, probably repeated after [A], since such inaccuracies in the notation of accidentals are typical of Chopin. The sharp was added in EE and in GE3; in the latter, another defect of Chopin's notation was removed – the unnecessarily repeated before a
2 in the 3rd group of semiquavers. The sharp in the discussed place could have been added in FEH – see the adjacent note.
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources
issues: EE revisions, Errors in FE, Accidentals in different octaves, GE revisions, Cautionary accidentals, Omission of current key accidentals, Last key signature sign, Errors repeated in GE
notation: Pitch