Why the marginal histograms countings n Vega-Lite is wrong?

Dear all, as can be seen in the following link, the marginal countings are wrong edited. For example, in marginalHistograms_1, the top histogram failed to count the numbers between 0 to almost 200 of A axis, where the orange dots concentrate. Could anyone tell me where should I modify? Thank you very much!

https://observablehq.com/d/e2a6517f9d5b4cd0