In GC (→GE) and FE1 (→FE2→EE) there is no accidental before the top most note of the last chord. This patent inaccuracy of Chopin notation was corrected in FE3 (→FE4), at the same time, however, the 
raising a
1 to a1 was overlooked.
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources
issues: Errors in FE, Inaccuracies in GE, Inaccuracies in FE, Errors resulting from corrections, Omission of current key accidentals, EE inaccuracies, FE revisions, Last key signature sign, Inaccuracies in GC
notation: Pitch