[BUG][KOTLIN] Generator printing warnings for type-mapped class

Description

I'm trying to generate Kotlin code using a mapped type Feature that I want to provide. The generated code looks correct, but the plugin prints a warning line:

Unknown type found in the schema: Feature

Am I configuring something incorrectly and that line can go away?

I have a minimal example at https://github.com/andrewparmet/test-openapi-kotlin-type-mapping.

My config, in particular for type mappings:
https://github.com/andrewparmet/test-openapi-kotlin-type-mapping/blob/master/build.gradle.kts#L17-L18

In fact, I can remove those two lines altogether or include one or the other and nothing changes. My impression from the documentation is that I want them and they should be responsible for this warning. Is there something I'm missing?

openapi-generator version

4.3.1

OpenAPI declaration file content or url

https://github.com/andrewparmet/test-openapi-kotlin-type-mapping/blob/master/src/main/resources/test-api.yaml

Generation Details

Gradle plugin.

Steps to reproduce

./gradlew build in the directory of the attached project.

Suggest a fix

I can ignore this warning since the generated code is correct, but I want to see if it can be removed.

Reproduce the warning with ./gradlew build in the linked minimal project. Inspect build.gradle.kts lines 17-18 and src/main/resources/test-api.yaml, then trace how the Kotlin generator handles the mapped Feature type; done means the warning is removed while generated code remains correct.