@Alexander: The package build uses the p2 metadata which should reflect the OSGi dependency structure but there may be deviations. In the end, it tries to predict what will happen during runtime, but many things can potentially go wrong between build time (p2) and run time when OSGi tries to resolve the dependencies. In this case I would suggest to use tools like the OSGi console to find out the reason for bundles not being started, services not available, etc.
By looking into one of the earlier builds, e.g. #667, you can see in the build log that it failed because of a missing dependency of the parallel feature.
