1-a1 in 
The version of EE1, repeated then in all analogous bars (b. 227, 243 and 247), could have been the initial version of these bars. However, it seems to be more likely that we are dealing here with Chopin's inadvertence, corrected in the penultimate stage of proofreading of FE (→GE). The correction was also introduced in EE2, probably on the basis of GE1. The a1 note is featured in the violas part, yet only just on the 3rd beat of the bar (after the rests).
Compare the passage in the sources»
category imprint: Interpretations within context; Differences between sources
issues: EE revisions, Omission of current key accidentals, Authentic corrections of FE, Last key signature sign
notation: Pitch