in 
In the sources, there is no 
under the turn mark; however, the 'post' visible within the mark of FE – 
– was used to mark that the bottom note of the turn is to be raised (see, e.g. the Nocturne in B major, op. 62 no. 1, bar 21, in which Chopin marked a turn with the 
mark in one of the autographs, whereas in another one, he wrote it with small notes, the bottom of which is raised). It is also noteworthy that the mark in FE is reversed, which may suggest an unnatural order of the interchanged notes in this context (first the bottom, then the top one). Such a notation, probably accidental, was not repeated both in GE and EE. In the main text, we give the generally adopted notation corresponding to the most likely performance of the turn.
Compare the passage in the sources»
category imprint: Interpretations within context; Differences between sources
issues: EE revisions, Inaccuracies in FE, GE revisions
notation: Ornaments