@AfterMapping methods are called twice when target uses Lombok @Builder annotation

Expected behavior

Generated code calls @AfterMapping method only once. Here is the generated output for MapStruct 1.5.5:

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2024-08-19T16:21:29+0200",
    comments = "version: 1.5.5.Final, compiler: javac, environment: Java 21.0.2 (Oracle Corporation)"
)
class MappingExample$SimpleSourceDestinationMapperImpl extends MappingExample.SimpleSourceDestinationMapper {

    @Override
    MappingExample.SimpleDestination sourceToDestination(MappingExample.SimpleSource source) {
        if ( source == null ) {
            return null;
        }

        MappingExample.SimpleDestination.SimpleDestinationBuilder simpleDestination = MappingExample.SimpleDestination.builder();

        simpleDestination.name( source.getName() );
        simpleDestination.description( source.getDescription() );

        afterMapping( source );

        return simpleDestination.build();
    }
}

Actual behavior

@AfterMapping method is called before and after using the build() method of the builder pattern.

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    date = "2024-08-19T16:24:57+0200",
    comments = "version: 1.6.0, compiler: javac, environment: Java 21.0.2 (Oracle Corporation)"
)
class MappingExample$SimpleSourceDestinationMapperImpl extends MappingExample.SimpleSourceDestinationMapper {

    @Override
    MappingExample.SimpleDestination sourceToDestination(MappingExample.SimpleSource source) {
        if ( source == null ) {
            return null;
        }

        MappingExample.SimpleDestination.SimpleDestinationBuilder simpleDestination = MappingExample.SimpleDestination.builder();

        simpleDestination.name( source.getName() );
        simpleDestination.description( source.getDescription() );

        afterMapping( source );

        SimpleDestination simpleDestinationResult = simpleDestination.build();

        afterMapping( source );

        return simpleDestinationResult;
    }
}

Steps to reproduce the problem

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>test-mapstruct-issue</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>21</maven.compiler.source>
        <maven.compiler.target>21</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
            <version>1.6.0</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.34</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok-mapstruct-binding</artifactId>
            <version>0.2.0</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.11.0</version>
                <configuration>
                    <annotationProcessorPaths>
                        <path>
                            <groupId>org.mapstruct</groupId>
                            <artifactId>mapstruct-processor</artifactId>
                            <version>1.6.0</version>
                        </path>
                        <path>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                            <version>1.18.34</version>
                        </path>
                        <path>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok-mapstruct-binding</artifactId>
                            <version>0.2.0</version>
                        </path>
                    </annotationProcessorPaths>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Code example:

import lombok.Builder;
import lombok.Data;
import org.mapstruct.AfterMapping;
import org.mapstruct.Mapper;

public class MappingExample {

  @Data
  public static class SimpleSource {
    private String name;
    private String description;
  }

  @Data
  @Builder
  public static final class SimpleDestination {
    private final String name;
    private final String description;

  }

  @Mapper
  abstract static class SimpleSourceDestinationMapper {

    abstract SimpleDestination sourceToDestination(SimpleSource source);

    @AfterMapping
    void afterMapping(SimpleSource simpleSource) {
      // do something
    }
  }
}

MapStruct Version

MapStruct 1.6.0