The flats lowering d1-d2 to d1-d2 is an error of the engraver of FE1 (→FE2,EE). It is proven by the version of GE and Chopin's hand-written correction in FEJ. The correct text was also introduced into EE2.
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category imprint: Differences between sources
issues: Annotations in teaching copies, EE revisions, Errors in FE, Annotations in FEJ
notation: Pitch