The missing naturals lowering c and c1 to c and c1 in b. 97 in FE1 must be a mistake, committed probably by Chopin. It is indicated by the lack of planned space for naturals in GE1, which means that they were most probably absent in [A]; they could have been added in printing. The mistake was corrected in FE2 and EE.
Compare the passage in the sources »
category imprint: Differences between sources
issues: Errors in FE, Omission of current key accidentals, FE revisions
notation: Pitch