Is Gradle sonarqube task synchronous?

@ganncamp Thanks for the clarification.
This means that we have no way of failing the build and breaking the pipeline from Gradle.
We use GitLab CI ( GitLab Enterprise Edition 11.11.8-ee)
I have found this post: How to block the merge of Merge Requests when SonarQube Quality Gate is failed, with GitLab
But it’s mentioned that the feature is only availble on GitLab 12.5 and higher.
Is there any other way you can recommend to block Merge Requests in case of QG failure?