Issue with @Unindexed Annotation on java.util.Collections in Spring Data Cloud Datastore - Not Working as Expected

Question

We've been utilising Objectify for data persistence in Google Cloud Datastore, where the @Unindex annotation works seamlessly across all value types. However, upon transitioning to Spring Cloud Data Datastore, we expected similar functionality. Unfortunately, we've encountered an issue where @Unindex annotations within Map or List<Ref<?>> fields are not producing the expected outcome.

Environment Details:

Java 17 Spring Boot 3.2.3 Gradle 8.5

build.gradle

ext {
    set('springCloudGcpVersion', "5.0.4")
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'com.google.cloud:spring-cloud-gcp-starter'
    implementation 'com.google.cloud:spring-cloud-gcp-starter-data-datastore'
}

dependencyManagement {
    imports {
        mavenBom "com.google.cloud:spring-cloud-gcp-dependencies:${springCloudGcpVersion}"
    }
}

Entity Classes:

import com.google.cloud.spring.data.datastore.core.mapping.*;
import org.springframework.data.annotation.Id;

@Entity(name = "Library")
public class Library {
  @Id private String id = UUID.randomUUID().toString();
  @Unindexed private Map<String, Set<String>> attributes; // Unsuccessful unindexing
  @Unindexed private Set<Integer> sets; // Successfully unindexed
  @Unindexed @LazyReference private List<Book> bookRefs; // Unsuccessful unindexing
}

import com.google.cloud.datastore.Key;
import com.google.cloud.spring.data.datastore.core.mapping.*;
import org.springframework.data.annotation.Id;

@Entity
public class Book {
  @Id Key id;
  private String title;
}

Datastore Table Screenshot

We're seeking resolution to ensure consistent @Unindexing functionality across all relevant data types within Spring Cloud Data Datastore.

Any lead will be appreciated.

Thanks!