What am I missing here?

[LawBeefaroni]

The new crater is about 22 miles (36 km) across, which makes it the 22nd-largest impact crater ever discovered on Earth and a wee bit smaller than the Hiawatha crater, which measures 19 miles (31 km) across.

From here. Is there a different measurement of size I'm missing or did they get it wrong?

[Jaymann]

That's a deep question.

[stessier]

They messed up.

Forbes -

Thanks to the NASA satellites "Terra" and "Aqua" and using different wavelengths it is possible to look through the ice, mapping the rocky underground. Combining the data from the satellites with RADAR, gravity and magnetic surveys done by planes flying above Greenland, researchers generated a Digital Elevation Model (DEM) of the bedrock hidden beneath the one-mile thick ice sheet. A research team of the Goddard Space Flight Center in Greenbelt, Maryland, published an analysis of the DEM, suggesting that another circular depression can be found beneath the ice, likely a second impact crater. The research argues that the circular depression can't be explained as a volcanic caldera, as there are no recent volcanic rocks found in the area and there are no signs of magnetic anomalies, often associated with iron-rich volcanic rocks, to be found beneath the ice. The new crater is located just 114 miles away from the Hiawatha Crater and with 21 to 22 miles in diameter is slightly larger. It is not likely that both craters formed at the same time or during a single impact event. Based on ice thickness and rates of ice erosion, Hiawatha Crater is estimated to be 12,000 to 100,000 years old. The second crater is covered by thicker ice and appears more eroded, suggesting that it was formed at least 79,000 to 100,000 years ago.

Wikipedia - (shows everyone agrees on the size of Hiawatha)

In November 2018, a study revealed the existence of a large crater beneath Greenland's ice sheet in the Hiawatha Glacier region—a 31-kilometre-wide (19 mi) circular bedrock depression up to a kilometre below the surface of the ice.[6] The evidence suggests that the crater was created after ice covered Greenland three million years ago, and perhaps as recently as 12,000 years ago.[7][8]

[Archinerd]

Less is more.