Someone explained in another thread that the Devs have put it down to horribly cluttered original coding. The code is a mess in those original conversations and not a quick fix. This is why unify works in new cut scenes, but not any of the originals.
I very much feel your pain. I have a very nice kit for my entire Imperial Agent team and it looks like a hodge podge of garbage in the final clips.
This wouldn't surprise me. The Sith Warrior had buggy convos with Pierce for the longest time.... I just wish we could get a "Hey, we know about this and are looking into it."