Reserved keyword (?) in rel doesn't add curie

I have an IndexController that links to my public endpoints:

@GetMapping("/") public HttpEntity<ResourceSupport> exposeIndex() { ResourceSupport indexResource = new ResourceSupport(); indexResource.add(ControllerLinkBuilder.linkTo(AController.class).withRel("a")); indexResource.add(ControllerLinkBuilder.linkTo(BController.class).withRel("b")); indexResource.add(ControllerLinkBuilder.linkTo(ProfileController.class).withRel("profile")); return ok().body(indexResource); }

In my SpringBootApplication, I have this CurieProvider:
@Bean public CurieProvider curieProvider() { return new DefaultCurieProvider("ns", new UriTemplate("/api-docs/api-guide.html#resources-{rel}")); }

In the IndexController, the link to the ProfileController has no currie. The other links are correct.

When I change it's rel to "prof", all links are correct.

Start with the IndexController example and the CurieProvider configuration, then trace how DefaultCurieProvider handles the rel value "profile" versus "prof". Reproduce the missing CURIE and identify the relevant Spring HATEOAS link or CURIE tests; done means the "profile" relation receives the expected CURIE without breaking the other relations.