In GE1 (→GE2), there is no 
before the second quaver. It must be a mistake – between two bars based on the same four-note diminished chord containing g, a possible g
would require a cautionary 
, not to mention the tied g in violin II. It was most probably [A] that was the source of the mistake, since the in FE was added only just in print. The mark was added in GE3.
Compare the passage in the sources »
category imprint: Interpretations within context; Differences between sources
issues: GE revisions, Omission of current key accidentals, Authentic corrections of FE, Errors repeated in GE
notation: Pitch