Replacing even values with a dotted rhythm is one of the most frequently encountered rhythmic diversifications in Chopin's music. All notes in the R.H. are placed in A exactly above the crotchets in the L.H., which may mean that Chopin introduced this diversification already after having written the earlier version, as a correction (similarly, in bar 77).
Compare the passage in the sources »
category imprint: Differences between sources; Corrections & alterations
issues: Dotted or even rhythm
notation: Rhythm