The initial eror is happening because in the "repository server" (nexus) are 2 artifacts (the slf4j-api.jar and the api-test.jar) which both use the same BundleSymbolic Name (which is not "allowed").
And then things somehow getting mixed up and at the end the resolving fails with some kind of md5 hash error.

the test-jar needs a different bundle name and everything should be fine.

Thanks for looking into this!