The version of GE1a is most probably a mistake by the engraver, although one cannot completely exclude a revision – the cautionary 
to b
, present in the remaining sources, is not indispensable here and could have been considered erroneous. The engraver or reviser of GE1a was similarly overly zealous in, e.g. b. 232.
In A there is no 
raising e1 to e1 in this chord. It is almost certainly a mistake – cf. e1 in b. 240-241 – corrected by FE (→GE,EE). In the main text we omit the cautionary to b, more justified in the original layout, in which the first 5 quavers in the previous bar – to b – are written down on the bottom stave.
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources; Editorial revisions
issues: Errors in GE, Cautionary accidentals, Authentic corrections of FE, FE revisions
notation: Pitch