Exporting a scattergl plot with large data sometimes takes forever

[gygabyte017]

I have this image, with about 1.5 million points and three coordinates to plot on a scatterplotgl (x, y, color).

However either with image.write_image('file.jpg') and with orca.CMD graph image.json -o file.jpg --verbose it takes forever and the image is never rendered (I can't figure out what it is doing).

Tried with other 1.5 million points data, sometimes it works within 60 seconds, sometimes just hangs. What is wrong? I attach the image json.

image.zip