This cannot be reproduced on 17.8.0RC1. But, you have to be aware that the IDs start number depends on the other trees displayed in the UI: you might have first node starting with j1_1 or j2_1 or j3_1 etc. And this might be random dependending what's loaded first in XWiki. So you might have the feeling that the issue reproduces just because of this, and right now there's no standard way to define a stable ID for static trees, so this shouldn't be considered as an API.
This message was sent by Atlassian Jira (v9.3.0#930000-sha1:287aeb6)
If image attachments aren't displayed, see this article.
