It seems that sunburst doesn't handle well very small numbers.
It looks like some coordinate is overfloated and it shows a small-valued beam as a fully filled layer, which covers the others beams.
Please check the data structure in my code example below.

Screenshots

Code example: https://codesandbox.io/s/nivo-sunburst-f7i02?file=/src/data.json:8237-8284

• OS: MacOS
• Browser Chrome 81
• Version @nivo/sunburst": "^0.61.0