Maven artifact repository: Two artifacts created instead of one, when uploading with Gradle

Summary

Artifacts pushed to the new Maven artifact repository using Gradle and the maven-publish Gradle plugin are appearing as two separate artifacts. One of them contains the *.jar file and the *.pom file, the other one only the maven-metadata.xml file.

Also I wasn't successful in downloading from the artifact repository, https://gitlab.com/api/v4/projects/8611940/packages/maven/org/openstreetmap/josm/plugins/Mapillary/Mapillary-v1.5.17.jar always gives a 404 Not found error for me. (edit: the URL works, I forgot the v1.5.17 subdirectory at the end of the URL)

Example Project

CI job, in which I uploaded an artifact: https://gitlab.com/JOSM/Mapillary/-/jobs/103060449

The two resulting artifacts: https://gitlab.com/JOSM/plugins/-/packages/189 and https://gitlab.com/JOSM/plugins/-/packages/190

What is the current bug behavior?

One artifact is uploaded, appears as two artifacts in the artifact repository

What is the expected correct behavior?

One uploaded artifact only results in one artifact in the repository.

Output of checks

This bug happens on GitLab.com