Well, I can confirm that my ongoing companion mod Vlja for Skyrim, which I have been working on since february and which has +3000 dialog entries stopped to work completely today. I have NOT been touching the esp since a few days ago, and then it worked just fine.
To specify it clearer:
If I start a game where my char hasn't met her, she will have no greetings at all, and accordingly also no dialog at all.
However, if I load a save where I already know her and have been travelling with her for a while, she will have greetings and dialog.
To check if it was a problem with the quest-script, I cloned a "Hello" and moved it to a new quest, which has no quest script. I gave it no conditions at all, i.e. it should show up during all circumstances.
Then I went back ingame to the save where I had not ever met vilja. Went to see her and she STILL had no dialog whatsoever.
I contacted a tester and asked him to check.
He had exactly the same result as me in his game.
As said before, I have not been touching the mod in the ck for a few days, so it's *not* something I have done today.
And I have *not* been using any COC.
One thing to note: Vilja has an esm-file + an esp-file.
EDIT: I can also confirm that saving the game and returning actually does cure it

.