I remember that, and it’s always vague on what a “weakness” is when that advice is given. It’s not really helpful when it isn’t explained.
A “weakness” isn’t “severe”. If you had a group that was one move away from dying, and you tenuki, that’s not a weakness thats severe. If you have a cutting point left over from a corner invasion (think the old 3-3 invasion sequence). That’s certainly a weakness and in the opening it’s not worthwhile to fix that cut, but eventually it will become significant enough to think about.
I think the following is “enough” to get by on when it comes to a weakness;
If it causes you worry or stress, fix it
If you’re thinking “it’s ok now but I wanna get back to it as soon as I can”, then it’s borderline. You might not get sente to fiX it and your opponent could attack that weakness. Sometimes it might work out just find and you get sente.
Who knows, but, deal with things before they become a problem for you. And conversely, cause problems for your opponent before they can fix them. You don’t need to play out the cut if you can make a cut, bit you may as well cut and then tenuki. Maybe your opponent spends 2 moves fixing it, so you get a free move. Maybe it becomes a winning move later, who knows.