There are a couple that are drawn from the American Community Survey, which uses 5-year averages to make up for its comparatively smaller sample size in each year. Since the latest 5-year window started before the 2020 Census, they have to be mapped as 2010 Census Tracts. So far so good.
I noticed that the entire state of Connecticut was missing from one of those layers, so I had to investigate. Sure enough, it's in the data table, so what's going wrong here? (2/?)