There is no 
lowering G to G
at the beginning of the bar in FE (→EE1). This mistake, if committed by Chopin, would prove his anticipatory thinking – modulation to the key of B minor/G major was already determined in the previous bar, hence the use of G could have already been considered obvious (in FE the spaces between the notes suggest that the before g and maybe even all 3 L.H. flats were added at the time of proofreading). The accidental was added in the remaining editions.
Compare the passage in the sources»
category imprint: Interpretations within context; Differences between sources
issues: EE revisions, Errors in FE, GE revisions, Omission of current key accidentals, Errors repeated in EE
notation: Pitch