When adding a new polygon, double-click to complete the process, but an extra vertex will be added at this time.
In the case of a triangle, it will look like this
Click twice to create two dots, and double-click to create four dots at the end.
Click three times to make three dots, and then double-click to make five dots.
A double-click minute is added.
Chrome system seems to be NG.
https://developers.arcgis.com/javascript/3/samples/ed_feature_creation/
For some reason, some PCs reproduce and others do not.
Does this have something to do with the graphics board?
The API uses the following
https://developers.arcgis.com/javascript/3/jsapi/draw-amd.html