Ah, dunno…I picked mine up at B&N, so no shipping...my room is warm most of the time....but not like burning hot. I'm terrible at guaging temperature though, so who knows maybe it's warmer than I think. Well, I guess it could be the environment, but not many of my other volumes are peeling. My Dragon Ball and RuroKen volumes have seen better days but they were bought between 2003 and 2006, and I lent a few to friends back then and was so stupid as to carry them around in my bookbag for the bus ride home, so some got kinda beat up. The binding quality really wasn't that great back then.
But I mean...up until now it's been Naruto 47, One Piece 20, HxH 20, HxH 21, and MAYBE a few others that peeled....
from the speed-up so far it's been volumes 28, 29, 30, 33, 34, 35, 37, 38, 39, 40, 42, 44, 45, 51, and 52....volumes 30, 33, 44, 45, and 51 it's just the bottom front corner...but 28, 29, 34, 37, and 52 had more significant parts peeling off =/
My copy of volumes 1, 2, 3, and 4 are all first printings...1 is actually a second printing...but they were all bought back in 2003 / 2004 and B&N NEVER had volume 1 so when it turned up I grabbed it (only volumes 1 - 3 of One Piece were out at the time), even though it was a little damaged....
I'm thinking about picking up newer copies of just 1 - 4 so I can put away my old copies to preserve them....they have Zoro in them lol