In A there is no 
lowering a1 to a1 in the chord on the 2nd quaver of the bar. It is a patent error, comprehensible when we realise that first Chopin wrote the part of the R.H., probably in a half-bar long fragments, and then he wrote the part of the L.H. At the moment of writing the discussed chord, a as an element of the prevailing harmony was already grounded in his awareness. The accidental was added in FE (→GE,EE).
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources
issues: Accidentals in different octaves, Errors of A, Authentic corrections of FE
notation: Pitch