When I was in my world this morning, I found a bunch of missing texture blocks in the place of a bunch of my cobwebs. So then I pick-blocked it, and it turned out to be a cobweb.
MC-52534
Missing Texture cobweb blocks that were placed in 14w11a and lower
Resolved
Invalid
0
Cobweb was placed with a data value greater than zero. This is rendering a missing texture in 14w11b, since there is no
minecraft:cobweb:1