Fat lines example issue

I tried to recreate the fat lines example https://threejs.org/examples/?q=fat%20li#webgl_lines_fat but I ran into an issue when using LineGeometry with worldUnits and alphaToCoverage, then I get these ugly circle lines appearing on my fat lines:

I tried recreating the example line by line and have the latest Three.js version installed so I cannot find what is the difference between the example and my local machine.

Any idea what I might be doing wrong?

For reference this is a picture comparing my results with alphaToCoverage turned off/on. The whiteish circles appear only when alphaToCoverage is enabled, but I want to have it enabled to make the edges smoother.