In A1 (→FE) there is no 
lowering e1 to e
1. It is a result of inattention at the time of performing corrections in this autograph: originally, it was a crotchet featuring e1 alongside the necessary that was on the 1st beat in the R.H. bottom voice. Chopin did not control the notation of accidentals after he had replaced it with a rest. The sign was added in EE; it is also in GE, which could also be explained by an editorial revision.
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources
issues: EE revisions, Errors resulting from corrections, GE revisions, Errors of A, Errors repeated in FE
notation: Pitch