I ran into a similar problem. To clarify what happened, I was able to research 2 of the 3 tech tree items need to unlock the titans. I can build the Allegiance class titan (playing as empire) and have deployed a few of them. However, the other star dreadnought design tech is blanked out and says "requires faction" as the missing requirement. As a result I can't research or deploy the Executor. I have however encountered one deployed by one of the computer players. If there is something else I am missing please let me know.
