Wrong version of maven-archetype-plugin running "mvn archetype:generate"

Question

I created an archetype with maven, which includes archetype-post-generate.groovy, but it is not executed.

This is a fragment of the pom:

<properties>
    <maven.archetype.version>3.2.0</maven.archetype.version>
</properties>

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-archetype-plugin</artifactId>
                <version>${maven.archetype.version}</version>
            </plugin>
        </plugins>
    </pluginManagement>

    <extensions>
        <extension>
            <groupId>org.apache.maven.archetype</groupId>
            <artifactId>archetype-packaging</artifactId>
            <version>${maven.archetype.version}</version>
        </extension>
    </extensions>
</build>

However, the version of the plugin does not match the one defined in the pom:

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------< org.apache.maven:standalone-pom >-------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] --------------------------------[ pom ]---------------------------------
[INFO]
[INFO] >>> maven-archetype-plugin:2.4:generate (default-cli) > generate-sources @ standalone-pom >>>
[INFO]
[INFO] <<< maven-archetype-plugin:2.4:generate (default-cli) < generate-sources @ standalone-pom <<<
[INFO]
[INFO]
[INFO] --- maven-archetype-plugin:2.4:generate (default-cli) @ standalone-pom ---
[INFO] Generating project in Interactive mode

Could that be the reason why it doesn't run the groovy script? Why does the version not match?

EDIT: Complete POM with suggested changes:

<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>

    <artifactId>bp-archetype-bcore</artifactId>
    <groupId>global.base</groupId>
    <version>1.0.0</version>
    <packaging>maven-archetype</packaging>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-archetype-plugin</artifactId>
                <version>${maven.archetype.version}</version>
            </plugin>
        </plugins>

        <extensions>
            <extension>
                <groupId>org.apache.maven.archetype</groupId>
                <artifactId>archetype-packaging</artifactId>
                <version>${maven.archetype.version}</version>
            </extension>
        </extensions>
    </build>

</project>

Answer 1

Declaring a plugin just in <pluginManagement> adds nothing to the build. This is just kind of a template which configuration should be used if the plugin is declared in this or a child POM's <build><plugins> section.

See POM Reference, Plugin Management:

• pluginManagement: [...] However, this only configures plugins that are actually referenced within the plugins element in the children or in the current POM. [...]