The combination of slurs and sempre legatiss. that Chopin used in A was one of his ways to mark the "harmonic legato"- sustaining the parts of the harmony with the fingers. Omission of the verbal indication in GE1 made it considerably more difficult to figure out the proper way of performance (the slurs that were preserved are binding anyway, almost throughout the Nocturne, on the basis of the slurs in bar 1). Correcting FE, Chopin probably noticed that fact and changed the markings so as to indicate more strongly the special type of performance in that and several subsequent bars. What draws our attention here is the removal of slurs that were present in A. In our opinion, this is due to the fact that – particularly in bar 22 – the "harmonic legato" is carried out by sustaining notes in the middle of the bar, which is not in line with the slurs that are divided in that very point: 
(if the hand span is insufficient, the sustaining of the note e flat1 may be omitted or performed with the right hand).
In GE2, the version of A was restored, which complies with the direction of the adjustments made in that edition. The notation of EE3 was also supplemented with the slurs present in GE. None of those changes may possibly come from Chopin.
category imprint: Differences between sources; Corrections & alterations
issues: EE revisions, Errors in GE, Authentic corrections of FE
notation: Verbal indications
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