In the main text we add a cautionary 
before b2 in b. 501. In A one can see that Chopin crossed out that accidental; however, he inserted a before b1 in an analogous situation in b. 505. The accidental was added also in EE and GE2 (→GE3). Moreover, we remove the poorly justified before b on the 3rd beat of b. 503, present in all sources. In this context Chopin was also inconsistent, since he did not write a in b. 501.
See b. 494-496
Compare the passage in the sources»
category imprint: Differences between sources; Editorial revisions; Source & stylistic information
issues: GE revisions, Cautionary accidentals, Deletions in A
notation: Pitch