Pitest does not create XML report even with the given XML option

I have been using Pitest generating mutation XML reports for a couple of Java projects. However, when I was generating a XML mutation report for the Apache Commons Math library, after a ~3 hour run, I only end up having HTML reports and I cannot figure out what causes Pitest to generate HTML reports instead of and XML report.

I am using the maven for Pitest, and I am using the configurations as below.

<plugin>
    <groupId>org.pitest</groupId>
    <artifactId>pitest-maven</artifactId>
    <version>1.5.2</version>
    <dependencies>
        <dependency>
            <groupId>org.pitest</groupId>
            <artifactId>pitest-junit5-plugin</artifactId>
            <version>0.8</version>
        </dependency>
    </dependencies>
    <configuration>
        <mutators>
            <mutator>DEFAULTS</mutator>
        </mutators>
        <targetTests>
            <param>*Test</param>
        </targetTests>
        <threads>8</threads>
        <fullMutationMatrix>true</fullMutationMatrix>
        <outputFormats>
            <param>XML</param>
        </outputFormats>
    </configuration>
</plugin>

Finally, to run Pitest I use the command below.

mvn org.pitest:pitest-maven:mutationCoverage

Any help would be great! Thanks!