From the Robert Jordan newsgroup (not my own words):

Something very strange happened between 10 and 20 years ago. In TGH: 4, 58, Summoned, 49 the Amyrlin says to Moiraine
"I am the fifth in a row raised to the Amyrlin Seat from the Blue." Two pages earlier, we learn that Siuan Sanche has been
Amyrlin for ten years. In TFoH: 15, 301, What Can Be Learned in Dreams, 214, Moiraine says to Egwene: "In a few
months it will be twenty-one years since we began the search for the Dragon Reborn. Sieren Vayu was raised to Amyrlin
shortly after, a Gray with more than a touch of Red in her." (C. Footman) This has been admitted by RJ as an error.

The correct sequence is:

Kirin Nelway (Brown) 922-950 NE
Noane Mosadim (Blue) 950-973 NE
Tamra Ospenya (Blue), 973-979 NE
Sierin Vayu (Gray), 979-984 NE
Marith Jaen (Blue), 984-988 NE
Suian Sanche (blue), raised 998 NE

The correction is being made in the body of The Great Hunt and in the glossary. (Robert Jordan, courtesy of Carolyn F)

The quick succession of Amyrlins prior to SS is discussed in further detail in ACOS.

In TFoH: 36, 578, A New Name, 409, Birgitte tells Elayne "You saved my life, Daughter-Heir of Andor. I will keep your
secret and serve you as Warder." But, later in TFoH: 47, 775-6, The Price of a Ship, 550 Birgitte verbally scolds Elayne for
telling Cerandin she was heir to a throne, and doesn't believe it until Nynaeve makes an offhand comment in TFoH: 49, 803,
To Boannda, 570.

Rand balefires Rahvin, erasing his actions, etc. However, none of Rand's injuries, all sustained at the hands of Rahvin,
disappear -- they were instead Healed by Nynaeve afterwards. (TFoH: 55, 949, The Threads Burn, 672-3 from Sean
Hillyard)