In the majority of the sources there is no accidental to the 8th semiquaver in b. 104 and 108. Admittedly, any doubt is dispelled by the following f
3 semiquaver, but the absence of the 
restoring f3 after f2 at the beginning of the bar must be considered a mistake due to the rule (frequently applied in the sources of the Variations) according to which accidentals are valid at a given pitch regardless of the use of an octave sign – cf., e.g. b. 35, 39 or 335. Therefore, we add them both in the main text and in the content transcriptions of the sources (versions "edited text"). Naturals were also added in GE3.
Compare the passage in the sources»
category imprint: Interpretations within context; Differences between sources; Editorial revisions
issues: Accidentals in different octaves, Omissions to cancel alteration, GE revisions, Errors repeated in GE, Errors repeated in FE, Errors repeated in EE
notation: Pitch