Weird slugificiation errors

[cabo]

Describe the issue

In a PR to jsonpath-base, we get weird errors about one of the unnumbered section names.

draft-ietf-jsonpath-base.xml(493): Error: Invalid attribute slugifiedName for element name, at /rfc/middle/section[3]/section[3]/name
/Volumes/nar/Users/cabo-rescue/Documents/ietf/jsonpath-wg/internet-draft/draft-ietf-jsonpath-base.xml(16): Warning: Invalid document after running preptool.
(No source line available): Warning: Duplicate id="name-semantics" found in generated HTML.

Despite the "Error", the HTML (or TXT) is still built.
https://github.com/ietf-wg-jsonpath/draft-ietf-jsonpath-base/runs/8310507138?check_suite_focus=true

There is nothing special about this fifth subsection named semantics that we can find; it seems to work for the others.
draft-ietf-jsonpath-base-weird.xml.txt
draft-ietf-jsonpath-base-weird.html.txt

Code of Conduct

• I agree to follow the IETF's Code of Conduct

[jrlevine]

I think the problem is that the preptool invents IDs for sections of the form "name-foo" where foo is the section name so if you have a section called foo and an id name-foo, that will collide.