According to us, it is highly likely that 
was accidentally overlooked by the engraver of FE (→GE,EE). If we were to look at the elements closest to the E1-E octave, the mark could have been easily taken for, e.g. a pedal release mark. On the other hand, Chopin proofread the Ballade quite exactly, hence in the majority of the situations it can be considered that the text of FE was accepted. Therefore, in the main text we suggest a variant solution.
Compare the passage in the sources »
category imprint: Differences between sources
issues: Errors in FE
notation: Verbal indications