[BUG] Python: "Only the HandlebarsEngineAdapter is supported for this generator"

I don't honestly know if this is a bug or something I am doing wrong, but would appreciate some help regardless.

I am trying to generate a Python client from an OpenAPI 3.0.1 file using the Maven plugin configured as follows. But when I do I get the error: "Only the HandlebarsEngineAdapter is supported for this generator". I am not specifying an Engine Adaptor, and I understand Handlebars is the default. What could be causing this? Thanks!

<plugin>
    <groupId>org.openapitools</groupId>
    <artifactId>openapi-generator-maven-plugin</artifactId>
    <version>6.2.1</version>
    <executions>
        <execution>
            <goals>
                <goal>generate</goal>
            </goals>
            <configuration>
                <inputSpec>${project.basedir}/target/openapi.json</inputSpec>
                <generatorName>python</generatorName>
                <configOptions>
                    <sourceFolder>src/gen/python/main</sourceFolder>
                </configOptions>
            </configuration>
        </execution>
    </executions>
</plugin>

Reproduce the Maven plugin configuration with OpenAPI 3.0.1 and the Python generator, then trace how the generator selects its template engine and handles the reported adapter error. Done means identifying whether the configuration or generator behavior causes the error and documenting a verified resolution.