Both "F"s appeared upside-down and inverted in transition, and Joyce corrected this in the proofs, but the order of upside-down F first and upside-down and inverted F second indicated in the Criterion revisions has been reversed here, and this is the order they appear in the final text.
All three stages of the Finnegans Wake galley-proofs (made directly from the corrections to the transition pages) show an upside-down and inverted "F" in both places (JJA 49: 163, 453; JJA 50: 163). These remain uncorrected on the galleys and on the extant addenda, and so the final correction must have been indicated on one of the many missing addenda to the galleys.