I got the impression that;
A) Nura has zero control of her visions. They happen when they happen. She *might* get a random vision of Yera being unmasked, or she might get a random vision of Violet in the future with her new haircut dating Ayla. Or neither. Her visions tend to be of big stuff that affects either the entire team, the entire world, or her personally. Something happening to a teammate that she has little interaction with seems a bit obscure for her power to latch onto. But yeah, it's just random chance that she *didn't* get a vision involving Yera/Violet. Or a vision that the Earthgov vice-president was Universo. Or a vision that Orando was under attack and Karate Kid would lose his life freeing it. Or a vision that Brainy was gonna flip out and attempt to destroy the universe with Omega. Her visions have a spotty track record, at best.
I don't disagree that her precognition is not well-handled narratively, and should be a bit more consistently useful, but not plot-wrecking. That's a neat trick that even the best Legion writers haven't managed to pull off too often, IMO.
B) Imra, like most comic-book telepaths, seems to have some unwritten code of ethics about peeking into the minds of her allies, or teammates, and, all-too-often, not even scanning or verifying rando NPCs around them (leading to inevitable betrayals or impersonations, like the aforementioned Universo-pretending-to-be-Gupta, sneaking past her scrutiny). If she and Violet were written as besties who spent a lot of time together, I'd be more critical of her not picking up on Violet having different thoughts (since, even if she is scrupulous about not plundering her friends brains, there's gotta be some leakage).
I also think that teams with telepaths shouldn't have this sort of problem. The average X-team over at Marvel has at least one telepath, often times folk like Emma Frost with far more flexible ethical codes than Imra, and yet their teams also get infiltrated by Dark Beast or Mystique or tricked by 'not really reformed' villains like Sabertooth-pretending-to-be-reformed, so they have even *less* excuse for this stuff happening.
In both of these cases, it makes senses within the story that Nura and Imra might not catch on, but it also is closely tied into a comics-wide issue of writers conveniently ignoring powers that invalidate the plot they want to tell that month. Dawnstar can track anything, but never seems to be able to find the thing what needs to be found for this months mystery. Nura can dream the future, but doesn't seem to catch the important stuff that would short circuit the current plot.
A writer who sits down to write a story involving telepaths and precognitives and super-geniuses and people who can move at lightspeed needs to adjust their eight basic plots to accommodate the characters abilities. That isn't easy. But that's the job.