According to the principles governing use of cautionary accidentals that we have adopted, the 
before g flat in the 3rd chord is unnecessary. The reason why Chopin put it in A (→GE→FE→EE) was probably the non-typical chord orthography that may bring associations with the diminished triad g - c sharp1- e1. Chopin introduced that enharmonically changed notation in the last phase of writing A, which is testified by the visible deletion of the chord originally written as the previous one.
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category imprint: Corrections & alterations; Source & stylistic information
issues: Corrections in A, Cautionary accidentals, Enharmonic corrections
notation: Pitch