Description
When setting selectedpoints on a scattergl trace for curvenumbers > 0, the markers disappear - for curvenumber 0 it works as expected.
Screenshots/Video
Works as expected:
var curveNumber = 0;
var selected = [0, 1, 2];

Selected markers disappear:
var curveNumber = 1;
var selected = [0, 1, 2];

Steps to reproduce
Please switch between curveNumber = 0 and curveNumber = 1
https://codepen.io/ismirsehregal/pen/gbwgOWm
Notes
I posted the issue here first. However, this seems to be a plotly.js bug.
This might be related.