The missing naturals raising c
-c1 to c-c1 are almost certainly Chopin's mistake. It is indicated by the naturals added by Chopin in FES as well as by the cautionary 
written in A before c1 in the next bar (eventually crossed out), which suggests that Chopin assumed that it was c that was valid there*.
The naturals were added in EE and GE2 (→GE3).
* A precautionary approach should be taken in the case of a reasoning based on a cautionary accidental – in b. 12 in A we can also observe crossed-out flats before c-c1, although the sound of those notes had already been consolidated at the beginning of b. 10 (Chopin was not always certain which accidentals were included in the key signature).
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources; Source & stylistic information
issues: Annotations in teaching copies, EE revisions, GE revisions, Omission of current key accidentals, Deletions in A, Annotations in FES, Last key signature sign
notation: Pitch
