In A (→GC,FE1) there are no accidentals before the 4th chord. The overlooked 
lowering a2 to a
2 was also added in all remaining sources, while in FE2 (→FE3) a cautionary before a3 was added as well. Both signs added in FE2 probably result from Chopin's proofreading.
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources
issues: EE revisions, Accidentals in different octaves, GE revisions, Cautionary accidentals, Omission of current key accidentals, Authentic corrections of FE, Inaccuracies in A
notation: Pitch