I'm definitely right on this, they are a level range for the Zone level range, not your level when you loot the Cairn. As I said I have received different level items on 2 diff level toons on the SAME Cairns and Puzzles. I can name probably a dozen players in Guild with the exact same results, as well as maybe a dozen more on Shard again with the same results. You WILL NOT
get a level 50 item from Freemarch, or Stonefield, or other low level zone if you are level 50 when it is looted. And if you're so right then explain how my level 12/13 got level 20 items out of the Stonefield Cairns/Puzzle and level 15 items out of the Freemarch Cairns/Puzzle while being level 11, by your reasoning they should have been the level I was when I looted them.
The items seem to be Class specific, my Cleric has never gotten a Plate, Leather or Cloth item and my Rogue has never gotten a Plate, Chain or Cloth item. I will agree I haven't found any source online that states from a Trion dev that this is the case, I'm taking it from experience of myself and many dozens of players AND I have read on more than one forum post about Cairns/Puzzles that other players also see the same pattern, that is a level range based on the level range of the zone (min/max kinds thing).
To make this more clear I asked a 50 friend of mine today to go do the Scarwood Reach puzzle and Cairn (he hasn't done any of them to date). Once again he was LEVEL 50 and when looting the Cairn and Puzzle both items were level 40, the maximum appropriate level for that zone. You may want to do some research before blatantly calling someone out for being wrong ;)
DPS: (Inq) 51 (Sent) 10 (Ward) 5
Raid Healer: (Puri) 32 (Sent) 34 (Ward) 0
MT Healer: (Puri) 51 (Sent) 15 (Ward) 0
Tank: (Just) 47 (Sham) 7 (Inq) 12
Inquisicar: (Inq) 51 (Justi) 14 (Sent) 1