The omitted 
in FE1 lowering f
2 to f2 was added in FE2 and EE. GE also has a correct text.
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources
issues: EE revisions, Accidentals in different octaves, Inaccuracies in FE, Omission of current key accidentals, FE revisions
notation: Pitch