A line pointing down next to ledger lines (most of the time the first bottom one, i.e. c1 or E – see e.g. the last E
in bar 280), sometimes appearing in Chopin's autographs, misled here the engraver of GE. The additional stem is already absent in FE (→EE), which could have been, but did not have to, a result of Chopin's proofreading. However, one has to admit that in this case the extension of c1 is quite reasonable, as far as the harmony is concerned.
Compare the passage in the sources »
category imprint: Graphic ambiguousness; Differences between sources
issues: Authentic corrections of FE, Uncertain notes on ledger lines
notation: Rhythm