There is no doubt that the placement of the sign in the sources is incompatible with the notation of [A]. However, it does not have to mean that the dynamics is valid only from the 2nd beat of the bar, as Chopin would sometimes use an older convention of placing performance indications not at the beginning, but in the middle of the scope of its validity. According to us, such an interpretation is more likely here than a literal interpretation. Similarly in bars 29, 75 and 83, which in [A] (→GC) were marked as a repetition of bar 21.
Compare the passage in the sources »
category imprint: Interpretations within context; Editorial revisions
issues: Centrally placed marks
notation: Verbal indications