Fischer-Spassky Game #17 -- Threefold Repetition?

[HumbleProgrammer]

I was looking for some "threefold repetition" games to test a homebrew PGN tool, and remembered that the 1972 Fischer-Spassky match included several such draws. Sure enough, Game #17 is annotated as a threefold repetition draw on Wikipedia (and several other sites) but my tool failed to find it. Looking at the game, I don't see a threefold repetition either. Am I missing something here, or is Wikipedia misinformed?

[Event "Reykjavik-Wch"]<br> [Site "Reykjavik-Wch"]<br> [Date "1972.01.18"]<br> [EventDate "?"]<br> [Round "17"]<br> [Result "1/2-1/2"]<br> [White "Boris Spassky"]<br> [Black "Robert James Fischer"]<br> [ECO "B09"]<br> [PlyCount "89"]<br> <br> 1. e4 d6 2. d4 g6 3. Nc3 Nf6 4. f4 Bg7 5. Nf3 c5 6. dxc5 Qa5<br> 7. Bd3 Qxc5 8. Qe2 O-O 9. Be3 Qa5 10. O-O Bg4 11. Rad1 Nc6<br> 12. Bc4 Nh5 13. Bb3 Bxc3 14. bxc3 Qxc3 15. f5 Nf6 16. h3 Bxf3<br> 17. Qxf3 Na5 18. Rd3 Qc7 19. Bh6 Nxb3 20. cxb3 Qc5+ 21. Kh1<br> Qe5 22. Bxf8 Rxf8 23. Re3 Rc8 24. fxg6 hxg6 25. Qf4 Qxf4<br> 26. Rxf4 Nd7 27. Rf2 Ne5 28. Kh2 Rc1 29. Ree2 Nc6 30. Rc2 Re1<br> 31. Rfe2 Ra1 32. Kg3 Kg7 33. Rcd2 Rf1 34. Rf2 Re1 35. Rfe2 Rf1<br> 36. Re3 a6 37. Rc3 Re1 38. Rc4 Rf1 39. Rdc2 Ra1 40. Rf2 Re1<br> 41. Rfc2 g5 42. Rc1 Re2 43. R1c2 Re1 44. Rc1 Re2 45. R1c2<br> 1/2-1/2

Cheers!
Humble Programmer
,,,^..^,,,

[BB+]

This is just FIDE rules. You have to claim the draw before making the move that will produce a 3-rep. So Fischer claimed that Re1 would give a 3-rep (after moves 41, 43, 45). But the move is not made on the board. I have no idea how anyone came up with this rule, or its rationale, but it's what it is.