The slur b1-c2 in EE is certainly a mistakenly interpreted tie sustaining a1 (cf. the notation in A). Playing the a1 already at the beginning of the bar may result from a previous edition of this place, yet it seems that the rhythmic value assigned to the note is rather erroneous. Chopin would write semibreves in the middle of a bar (cf. the notation in the L.H. in A in bars 52-54 and analogous). Therefore, the only element which would differentiate a minim from a semibreve in this context was the minim's stem; if for any reason (e.g. due to deletions) the stem was not clearly visible, one could take the minim for a semibreve.
We should totally reject the (theoretical) possibility that the semibreve is a result of Chopin's correction in the manuscript serving as the base text for EE due to coherence of A and FE and {{the general characteristic} link} of EE.
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category imprint: Differences between sources
notation: Rhythm