Wingmaw on Tython is bugged for me and so is Savrip on Ord Mantell. Oh and a Datacron on Courscant, says there are 6 in the Codex but all the guides say there are only five.
You need to kill the Champion Savrip to get the Savrip bestiary update for Ord Mantell.
Also, looking at notes I made for my Jedi earlier, apparently you will get Wingmaw (for Tython codex) on Balmorra, not Tython. My notes said there is a quest on Taris that will send you there. And to quote a helpful player (don't have the name anymore, sorry
"I got my codex entry from “Scavenging Wingmaw”, at the area before Sundari Flatlands X: 283 Y: 1794 .
Gives codex entry for Balmorra and Tython."
(for Republic - but Empire would be in same area)
While I'm posting (which I do rarely) - I am also one of those players who likes to complete the codex in a zone before moving on. I started the game, and left for a while - because it's pretty disheartening to see that something this (seemingly) simple is not a priority at all. I'm playing because some of my daughter's friends are playing - but I foresee leaving again soon if this continues to be ignored. It just leaves a bad taste - and sends the message (to me) -"we aren't really paying attention to detail, we are not concerned about having a polished game, we've moved on." I imagine that a lot of the F2Per's will want to be completing their codex entries also - will that make a difference? I hope so ...