Why is micronaut invoking the wrong controller method? - groovy

Question

I have a micronaut API like this:
#Get("/")
List<Club> listClubs()
#Get("/{id}")
Club show(Long id)
In my unit test, when I invoke the show method, the listClubs() method is actually getting invoked, instead.
Why is this happening?
Details:
Thinking that my URL mappings must be wrong, I started debugging into Netty to try to understand how the framework constructs URLs.
In HttpClientIntroductionAdvice, the context shows the API method like this:
Club show(Long param0)
The interceptor is setting param0 in the parameter map, which doesn't match the actual parameter name of my method. When the URI template is expanded, this causes the ID to get dropped (thus the URI becomes / instead of /1).
I am trying to follow this example:
https://github.com/alvarosanchez/micronaut-workshop/tree/master/ex02/solution/clubs
There is one important different in my project, which is that the endpoint is set at "/club" instead of at "/":
#Controller("/club")
#Client("/club")
I am using a diff tool to compare my project to the sample, but I am struggling to find any other difference (besides package name changes).
Why is this happening? What should I be looking for?
Thanks
Update:
Tested the target endpoint with the browser - looks fine.
Gradle clean does not resolve the issue.
I switched from debugging the Application class with IntelliJ to using "gradlew run" and in the process, I made a change to build.gradle (adding JVM properties pass-through from the gradle CLI). I also played with enabling/disabling the annotation processor in the IDE.
(note: In the previous project, I enabled annotation processing as soon as I imported into the IDE. On this project, I didn't enable it until I started having issues.)
I think the build.gradle alteration caused the problem to go away. Since the issue shows up unreliably, it's hard to tell for certain if this is the change that caused it to be fixed.