When viewing a build/slave node on jenkins (e.g. localhost:8080/computer/MyNode/, it lists the associated jobs in a simplified viewlist that can not be edited.

In that list, the custom icon shows up for each job. However, the image URL is wrong. It includes computer/MyNode in the path with the result of a broken image instead of showing the actual icon image.

The full image URL becomes e.g
http://localhost:8080/computer/MyNode/job/MyJob/customIcon?size=24x24