The authenticity of the published version is unquestionable – the naturals raising e
(1) to e(1) appear accordingly in all sources except for Afin. On the other hand, the same can be said of the version of Afin, with the cautionary 
before e1, written, after all, with Chopin's hand. According to us, it is, however, questionable to consider e(1) to be an equal alternative to e(1) of the published version:
- Afin was written six years after the Sonata's publishing, probably from memory – Chopin would play the piece in public still in the summer of 1848 – and with a visible haste. Therefore, nothing indicates that the composer paid any attention to the accuracy of the notation;
- the aim of this autograph was not to provide a score which could be used during a performance – it was a typical polite gift, a souvenir of a meeting with the Master;
-
it is likely that e(1) is a common mistake, a mechanical repetition of the model of progression as a result of distraction.
Compare the passage in the sources »
category imprint: Differences between sources
issues: Cautionary accidentals, Authentic post-publication changes and variants
notation: Pitch