We've been told roughly what the Eldari Pact is

seems to have a lot to do with fate as far as I can see

When they start messing with the boundaries (or crossing the boundaries) of the pact, they lose vision of possible strings of fate for cradle

Makiel says to Suriel that she din't break the pact, but someone else did That means that Eithan, just talking, and guiding Yerin and Lindon is breaking the pact? We can be pretty sure that Eithan is not messing with fate, because then he'd "know" that Shen would betray Aurelius etc

So him guiding the entire Aurelius clan, and influencing the black flame empire is not breaking the pact, but tutoring 2-3 kids is

It's possible that Makiel meant that suriel did it openly, restoring fate in a traceable way for other judges, and Oz did it hidden and secretly even if using no powers related to a judge or the way

But he's still only talking to people