It could be the Titans can travel forward in time, but it could be they are blind to some futures as well. Since we don't know how time travel would work for them it's quite possible that they are limited in by their own lack of a spark of imagination that is chaotic in nature.

Think of them like Azeroth's Time Lords. The Doctor would never have brought Rose back in time to see her father if he could have known she would've been an idiot and saved his life. But he also seems to know what's supposed to happen, and what will happen. He states once that he can see all the time lines, all at once, all the time. Sometimes that's different than what does happen, because humans are wild and free-willed creatures who sometimes do dumb things.

If one had the ability to see the future, and the ability to change it, the more you desired to change the more complex the calculations would be. Say you told yourself, "no matter what I see I won't change anything." There would be only one possible future. But if you see a mistake you will make, and think, "what If I don't do that." Now you have two possible futures. Fix another mistake? this is where it gets complicated... did the mistake happen the same way in both timelines? did It happen at all in one of them? The more you ponder the changes, the more opportunities for mistakes you have, branching out endlessly.

The ability to see the future out more than a day or two suddenly granted to a being of less than godlike intellect would probably just kill them. (outright from shock or slowly from not drinking do to being locked in a vegetative state as their mind endlessly ran though what-ifs)