in 
Bar 40 is the last one on the page in A, and, in spite of the fact that the slur suggests continuation in the next bar, there is no ending on a new page. In GE1, a slur was initially printed to the end of bar 40 and a new one from the beginning of bar 41 to the end of bar 44. The slurs were then corrected to the version written in A (probably at Chopin's request). FE (→EE) included the corrected version of the beginning of the slur in bar 41, but not of the ending of the slur from bar 40, which could mean that the correction was introduced in the last phase of proofreading of GE1.
Compare the passage in the sources »
category imprint: Differences between sources
issues: Authentic corrections of GE, Corrected slurs of Op. 21 in GE1
notation: Slurs