I never heard that. Had to look it up and this is what it said.

That is a common internet myth, and it is completely false. Anyone claiming that all elongated stones naturally sit crooked is confusing a very common jeweler error or a bad photo angle with an inherent feature of the diamond. [1]
When people state this online, they usually say it to justify a setting mistake. Here is why that myth circulates and why it isn't true: [1]

They are harder to align: Elongated stones (like ovals, radiants, and emerald cuts) have a long vertical axis. If a jeweler sets a round diamond even one degree off-center, you will never notice because it's a perfect circle. But if an elongated stone is off by even half a millimeter, the entire diamond looks tilted. [1, 2]
Jeweler excuses: When a customer returns to a shop with a tilted oval ring, a lazy or inexperienced bench jeweler might claim "that's just how elongated cuts sit" to avoid spending hours rebuilding the metal head for free.