Weird artifact on some hardwares

[etpinard]

See https://codepen.io/anon/pen/yZpXZE?editors=1010 which results in something like

(noticed that weird final red line segment) on some (macOS?) hardware.

See plotly/plotly.js#3522 for more details.

[dy]

That can be related with wrong handling of tail vertices. I noticed similar artifact too in related component gl-waveform.
I'd estimate that 3-4 hours of work.

[mofojed]

Let me know if there's anything else I can do to help test it out!