For EV, KP, and EC the Survived Codex entries just unlock when you beat the boss. For TFB the entire group must survive (with no revives) and you must do it on the first attempt during the raid.
That actually makes sense now. As I was pretty sure I died during one of the bosses of EV before and still got the survived codex entry.
Also on Kephess tfb, 1 of our ops team died in beginning of the fight, so I guess that was the reason of us not getting the codex entry.
My guess is the others just told me they got the codex entry but misunderstood me that I asked for the survived one.
Strange they would change it for TFB only than, without changing the description to "the entire team survived ..."
Also silly support just answered my bug report with "working as designed" instead of just telling me that for tfb they changed the "survived" context.
But what do you mean exactly with: you must do it on your first attempt?
Because I believe on the last boss we did wipe the first time, the second time(right after first wipe) we did it again, noone died and we did get the codex entry. Although it's been a while and can't be 100% sure.
I guess I will keep at it for a full run to find out.
Thanks for your replies.