Where we found the Seals, and their current state (broken or not):
So three seals are still intact (4, 5, and 7), although they are very, very weak. The intact ones are all in Rand's possession (or the possession of people on Rand's side). Also worth noting is that Rand is not aware of the seal Nynaeve found, or that it is broken already [COT: 24, A Strengthening Storm, 558-559].
In the Prologue of COT, Davram Bashere's wife Deira and Lord Dobraine are attacked, separately, in two apparent robbery attempts. We are not told what exactly the would-be thieves were looking for, but on discovering Dobraine, Loial blurts out, "'This is very bad! If there were more than two, Karldin, if they found - !'" [COT: Prologue, Glimmers of the Pattern, 93]. It's been speculated that Bashere and Dobraine were targeted in the belief or hope that they were guarding the seals still in Rand's possession.
Why now is not known, nor why Taim (almost certainly a Darkfriend) gave one to Rand in LOC if the Shadow was only going to want them back later. It's also not clear whether Bashere or Dobraine ever had the seals in the first place.