Scrappers are blessed (except maybe on Siege), but the Tome isn't blessed on any shard.
However, it sounds like you got hit by the "insurance bug" (misnamed, it also can and does hit blessed items), and the Ninja or Oni looted the book from your corpse after some of your items failed to stay with you.
It's an annoying bug, hits maybe 1 death out of every 10k deaths vs monsters on the shard, and is so rare that it's not reproducable by any known means (though it appears to be much more common in PvP, and some PvP groups know exploits that dramatically increase the chance of the bug hitting to about 1% instead of 1/100 of 1% versus monsters (enough that you hear someone complaining about losing insured and blessed stuff at Yew gate or champ about once every month on low-population shards, several times a week on high-pop shards like Atlantic).