FE has an a1 as the 3rd crotchet of the middle voice in the R.H. It is almost certainly the so-called Terzverschreibung error.
In GC (→GE1) the correct note is an f1. This patent error was corrected in GE2 (→GE3), EE also includes the correct version.
Compare the passage in the sources »
category imprint: Differences between sources
issues: Errors in FE, Omissions to cancel alteration, Errors in GE, Terzverschreibung error, GE revisions, Errors of GC
notation: Pitch