The alleged additional crotchet stem next to c1 visible in A is, according to us, an exceptionally imposing trace of Chopin's reflex at the time of writing notes on ledger lines. In order to secure visibility of such a note, the composer would give the note head the shape of a vertical line – see analogous note in bar 303. Sometimes, particularly when writing in haste (as in this case), the lines were long enough to look like a crotchet stem pointing downwards (a slightly shorter line in bar 301 did not mislead the engraver). See also the Etude in F major, Op. 10 No. 8, bars 4-7.
Compare the passage in the sources»
category imprint: Graphic ambiguousness; Differences between sources
issues: Uncertain notes on ledger lines, Inaccuracies in A
notation: Pitch