The version of A with the b
-f1 fifth is most probably a remaining element of an earlier version of this bar, with d as the bass note (see the previous note). In GE1 (→FE1) Chopin introduced a third instead of the fifth; however, the proofreading was performed inaccurately, forgetting about the 
before the bottom note. FE2 tried to correct this mistake, yet the added sign was misplaced before the top note. The correct text appears just in EE.
Compare the passage in the sources»
category imprint: Interpretations within context; Differences between sources
issues: EE revisions, Errors in FE, Errors resulting from corrections, Authentic corrections of FE
notation: Pitch