Why is underemployment always so high?

I saw a post a while back that mentioned in a recent quarter of 2025, the underemployment rate for college graduates was around 45%.

This seemed very alarming to be but when I look on the Federal Reserve Bank of New York website, it seems it's almost always above 40% as long as it's been measured. Why is this am I interpreting it wrong or has it always been like this?

People say in recent years it's gotten worse but it seems this has always been a huge issue how would this get fixed?