In the main text we add cautionary naturals before a and b in the L.H., and a2 and b2 in the R.H. The cautionary naturals were also added in GE1 (before b2), and further ones in GE2 (→GE3) – before a, a1 and a2.
The 
before a2 was written into A in the first, deleted attempt to notate the grace notes – Chopin started to write them with stems downwards but changed his mind after having written two of them. It is hard to determine wether the omission of the in the ultimate record was deliberate or accidental.
Compare the passage in the sources »
category imprint: Differences between sources; Editorial revisions; Corrections & alterations; Source & stylistic information
issues: Corrections in A, GE revisions, Cautionary accidentals, Deletions in A
notation: Pitch