Corner above the slot with white facing you; the edge is in the slot but flipped.
Algorithms
U' R U R' U F' U' F
8 moves
YOURS
U2 R U R' U' F' U F
8 moves
U2 R U R' F R' F' R
8 moves
U2 R U' R' U' F' U' F
8 moves
Relations
Mirror
F2L 36
Your algorithm backwards
F' U F U' R U' R' U
solves F2L 31
That's why your scrambles are never the inverse of the algorithm: you'd be practising F2L 31 without knowing it. CubeDojo builds a random state with this case and checks it comes out.