This sounds like bad science to me. Our current exoplanet detection methods are heavily skewed towards detecting larger planets, depending on factors like the size of the parent star as well. So the planets we know of at the moment are most likely not at all representative of every planet that exists out there. Seems like a terrible moment to draw these kind of conclusions.

Its a pattern in the data that’s consistent unless our observations are very strangely skewed. Even if it only shows that gigantic planets tend to come in matched sets within a solar system that is quite interesting. As the paper suggests it warrants more investigation which might show that the correlation is true for all planets forming together in a system or not. That might have to do with how often, major inward moving currents form in a solar nebula, changing the distribution of matter towards a few giants as in our own solar system, or perhaps the metalicity of the original disk material is a factor ie more frozen gas and less rock. In any case a very interesting result, especially if it continues to hold up. The Vera C. Rubin Observatory should over time add many additional exoplanets to our records as it will survey billions of stars and can detect planets in types of systems not currently covered by TESS.

Okay this is a very interesting article and it’s also freaking me out a bit

https://web.archive.org/web/20250318050538/https://arxiv.org/pdf/1706.06204