There isn't a definition of what is significant though - it's entirely DM fiat. .
This is at least as true at the world level as at the game level.
One of my biggest problems with this is at the world level. Basically, the Seer is saying "The next thing you do will succeed, the thing after will succeed incredibly well, and then you will fail" (dice read 12, 20, 3).
So, there is already the problem in how the heck, at the world level, the seer describes a 10 ("The next thing you do will succeed or fail depending upon how difficult the task" kinda works but doesn't differentiate between an 8 and a 12)
But even at the world level, what the heck does that mean? Is "the next thing" typing this entire message or typing one character in it?
And how the heck does one explain, in world, an area effect attack? In world, the character throwing his fireball isn't making separate attacks, in arbitrary order, against each character. Thats purely a game artifice. How does the character usefully use the knowledge that he is about to roll a 1, 20, 10)?
And you can't handle it by saying "The next attack you make will hit your enemies, hitting the one you hate the most by far the worst and missing your ally" (1, 14, 20) since the next action might be a skill check, or there might not be multiple enemies or whatever.
l recognize that I'm an outlier in caring that the world actually makes a bare modicum of sense. But I do and this is really going to hurt that. Both from the flavour perspective and from the "why is the dumb barbarian asking about the monster now?" or "Why does the wizard not care about this monster when he cared so much about what the last 20 monsters were? perspectives
Precognition type powers have always been a bit of a pain. The powers associated with this theme are actually quite reasonable. An interrupt to add to your defence makes conceptual sense.