The FE1 version must be erroneous, which is proven by the unfounded 
to the bottom note of the R.H. bottom voice third, f – the engraver (or perhaps already Fontana in [FC]) repeated here an accidental standing next to the right (bottom) note of the correct text, which is a, requiring a . The fact that the erroneous FE1 version also includes a to a clearly demonstrates that Chopin was not the only participant in the process of proofreading FE1 – a reviser was present as well. It seems highly unlikely that Chopin noticed the missing and did not realise that the entire third was misplaced. The correct text was introduced in FE2 (→EE), in this case most probably at Chopin's request.
Compare the passage in the sources»
category imprint: Differences between sources
issues: Errors in FE, Terzverschreibung error, Authentic corrections of FE, FE revisions
notation: Pitch