jacoco code coverage with integration tests and multi module project

Question

i am trying to get jacoco working, so it reports me my code coverage of my integration tests. Currently i have this setup

parent.pom
-- module1
-- module2
-- module3
-- module4
-- report

module 1 to 3 contains my source code, while module 4 contains a client, which runs the integration tests.

parent.pom includes the jacoco-plugin:

<plugin>
            <groupId>org.jacoco</groupId>
            <artifactId>jacoco-maven-plugin</artifactId>
            <version>0.7.9</version>
            <executions>
                <execution>
                    <id>prepare-unit-test-agent</id>
                    <phase>generate-test-sources</phase>
                    <configuration>
                        <append>true</append>


<destFile>${project.build.directory}/jacoco.exec</destFile>
                    </configuration>
                    <goals>
                        <goal>prepare-agent</goal>
                    </goals>
                </execution>
                <execution>
                    <id>prepare-it-test-agent</id>
                    <phase>pre-integration-test </phase>
                    <configuration>
                        <propertyName>failsafeArgLine</propertyName>
                        <destFile>${project.build.directory}/jacoco-it.exec</destFile>
                        <append>true</append>
                    </configuration>
                    <goals>
                        <goal>prepare-agent-integration</goal>
                    </goals>
                </execution>
                <execution>
                    <id>jacoco-site</id>
                    <phase>verify</phase>
                    <goals>
                        <goal>report-integration</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>`

report pom:

<plugin>
            <groupId>org.jacoco</groupId>
            <artifactId>jacoco-maven-plugin</artifactId>
            <executions>
                <execution>
                    <id>it-report</id>
                    <phase>verify</phase>
                    <goals>
                        <goal>report-aggregate</goal>
                    </goals>
                    <configuration>
                        <dataFileIncludes>
                            <dataFileInclude>**/jacoco.exec</dataFileInclude>
                            <dataFileInclude>**/jacoco-it.exec</dataFileInclude>
                        </dataFileIncludes>
                        <outputDirectory>${project.reporting.outputDirectory}/jacoco-overall</outputDirectory>
                    </configuration>
                </execution>
            </executions>
        </plugin>

in my report module, all other modules are imported as dependencie with scope = compile.

Now, the generated Coverage, only shows that the tests cover takes place in module 1. Since the logic is something like this: Module 3 = Interface Module 2 = Implementation of the Interfaces Module 1 = entities

it is strange that the Code of Module 2 and 3 are not shows as covered. All the tests call methods from Module 3.

Just for side info: Source is in Java, Tests are in groovy