Omission of the 
mark written in A may be considered as an ordinary error of the engraver of FE (→GE,EE). However, the consequence with which each mark indicating or strengthening the forte dynamics in the first 16 bars of the Etude (the first appears together with the new key in bar 17) suggests a possibility of them being removed by Chopin or at least his acceptance of their absence. In this case in the main text we leave the version of editions without determining the starting level of dynamics for bars 1-8. Cf. notes to bars 8 and 16.
Compare the passage in the sources»
category imprint: Differences between sources
issues: No initial dynamic marking, Authentic corrections of FE
notation: Verbal indications