The nasolabial fold — the line running from the side of the nose to the corner of the mouth — is the most reliably creasing spot on a mature face, and it creases for a reason that has very little to do with the quality of your makeup.
The mechanism, plainly. That skin is thicker than the under-eye, and it moves more than anywhere else on your face. Every word you say, every sip, every expression folds and unfolds it. Any product sitting in the groove is being kneaded by that movement, and kneading a film of foundation produces a visible line of foundation within an hour or two. The product has not failed; it has been worked.
What that tells you about the fix. You cannot stop the skin moving, and you cannot make a fold shallower with makeup. The only variable you control is how much product is in the crease — which is why nearly every effective fix on this page is a subtraction rather than a purchase.
The three things that make it worse, in order of how often they are the culprit. First, quantity: a base applied generously over the whole face deposits a disproportionate amount in the fold, because that is where product runs. Second, dryness: a dry crease edge grips product and dries it unevenly, so the line reads lighter and drier than the skin beside it. Third, powder: a heavy set over the area turns a soft film into a dry, cracked seam.
And one thing that helps before you touch a makeup bag. A hydrated fold is a shallower fold. Moisturizer, two full minutes to absorb, and only then base. This step costs nothing and changes the result more than any product swap. The best concealer for smile lines page covers product choice for the same area, and the why foundation settles guide covers the general mechanism.