In A (→FC,FE) there is not a single 
before the a notes (in various octaves). Such oversights of accidentals defining the current key are among the most frequent mistakes of Chopin. The accidentals were added in GE and EE. The same applies to the next three bars.
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources
issues: EE revisions, GE revisions, Omission of current key accidentals, Errors of A, Last key signature sign, Errors repeated in FE
notation: Pitch