I'm finding now in 1.11 there is a disproportionate number of cartographers compared to librarians as well: there seems to be MANY more catographers than librarians which is really frustrating!
This seems to be broken again in 1.9.4, I tried '/testfor @e[type=Item] {Item:{id:minecraft:sand,Damage:1s,Count:1}}' next to some dropped red sand and it gave the error message 'item.tile.sand.red did not match the required data structure'.
I'm finding now in 1.11 there is a disproportionate number of cartographers compared to librarians as well: there seems to be MANY more catographers than librarians which is really frustrating!