The general difference in the variants is either dyads on the 2nd and 3rd beats in AO or triads in the remaining sources - resulting from adding a b note to the dyads of AO.
In AE, Chopin originally wrote a crotchet, which, as it seems, he then changed to a minim; however, he did not remove the previously written value. Therefore, CX includes a simplified notation of this place - the minim only. Due to the lack of an unequivocal deletion, in AE we suggest a two-part writing with a minim and a crotchet.
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category imprint: Differences between sources; Corrections & alterations
notation: Pitch