Missing dependency in maven multi-module project

So I’m having a really weird issue with CircleCI and a multi-module maven project (https://github.com/RichardGladman/project-bluejay).

My project builds and the tests all pass locally.

When I push to github, or re-run the workflow, the CircleCI build fails as it can’t find the rest-backend jar which is a dependency of the web app.

When I ssh into the container, I can see that there is no target directory in the rest-backend project but running .mvnw clean and .mvnw integration-test completes as expected and all tests pass.

Does anyone have any idea where to start looking for the problem?