Enrich tool giving unexpected results for polygons within a single block group

Bianca

I am enriching a polygon layer with various socioeconomic data such as MHI and poverty rate. I am using ACS 2022 5-year estimates. Many of my polygons fall completely within a single block group, so I would expect them to have the same values as the block group. However this is not the case. I found this article- https://support.esri.com/en-us/knowledge-base/problem-statistically-invalid-results-is-returned-when--000023704, but this seems to only apply to population counts. Why would a polygon within a block group not have the same MHI and rates as the block group?