Why does my D3 v7.9.0 scatter plot fail to render points when using d3.schemeObservable10 for color scaling?

When upgrading to D3 version 7.9.0 I want to use the newly added d3.schemeObservable10 color palette for a scatter plot. The data binds correctly and SVG elements are created, but the circles remain invisible or are not styled as expected. I am unsure whether the issue stems from how the scheme is imported, how the scale is constructed, or a conflict with other D3 modules.

What steps can help isolate the problem? Are there known compatibility considerations when combining d3.schemeObservable10 with d3.scaleOrdinal? How can I verify that the color scale is returning valid values?