In FE, there is one mark before the 7th quaver, a 
at the pitch of b, so it is unclear whether it concerns the bottom note of the third (resulting in a
) or the top one (resulting in c1). In the orchestra, the chord features c1 in the viola part, both in MFrorch and FEorch. Two possibilities arise:
-
FE do not contain a manifest error, it is only the raising a to a (necessary) that was put a little bit too high; it leads to the version with c
1 (the 
from the 1st half of the bar is valid), in which the c1 note in violas is of a replaceable character. When reading FE, this version is a natural choice and this is how this place was interpreted in GE (however, adding a in the viola part) and EE. It cannot be excluded that it was performed in such a way by Chopin's pupils during lessons, hence the absence of corrections in the pupils' copies may point to c1. -
According to Chopin's intention, the sharp in FE was meant to restore c1, whereas the alteration of a to a, obvious with regard to the sharps in the R.H., was overlooked. Undoubtedly, c1 in violas definitely supports this version, since the use of a chord element is highly likely in such orchestral accompaniment. The pedalling also seems to favour this possibility, since a pedal release (or change) before the 4th crotchet in the bar in the version with c1 would not be necessary (cf. the authentic pedalling in a similar harmonic context in the Fantaisie in F minor, op. 49, bar 18).
Compare the passage in the sources »
category imprint: Graphic ambiguousness; Interpretations within context; Differences between sources
issues: EE revisions, Errors in FE, Inaccuracies in FE, GE revisions
notation: Pitch