General

Is the Codex is unreliable

I just recently started hunting nest golems.
Eventually i got their monster card which clearly shows what items and recipes they drop ( as they should with every monster).
But something unusual happened.
I continued hunting and i found this http://i56.tinypic.com/27y04rd.jpg
I checked the codex to see if it was in the droplist and to my surprise it wasnt.
http://i56.tinypic.com/6pti7t.jpg
http://i51.tinypic.com/5br5w4.jpg
http://i52.tinypic.com/2zg4s5f.jpg
http://i51.tinypic.com/2zdq8ld.jpg
http://i55.tinypic.com/2u5flmf.jpg
http://i52.tinypic.com/308lhr9.jpg

This means that other monsters may drop items that aren't listed in their droplist too. Which makes the codex an unreliable source for tracking drops.
What do you think?