The 
sign, unless it is a result of a misunderstanding, could have been added by Chopin in the proofreading of GE1. One could see here either a suggestion of a slightly changed dynamic concept, where the climax of the crescendo would fall already in the middle of this bar, or an ad hoc attempt to replace the overlooked dashes marking the range of the crescendo. Taking into account the above doubts, in the main text we preserve the notation of A without this sign – see the previous note.
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category imprint: Differences between sources
issues: Authentic corrections of GE
notation: Articulation, Accents, Hairpins