maven plugin fails to upload data if trac and jira plugin are both present

Maven plugin fails to upload data if trac and jira plugin are both present on a Sonar-2.2 installation. Error given by maven plugin is:

[INFO] Duplicate Keys not allowed. Duplicate for 'issues'

tested on both maven 2.2.1 (mvn sonar:sonar) and maven 3.0.0-beta2 (mvn org.codehaus.sonar:sonar-maven3-plugin:2.2:sonar).

Removing on of either trac or jira sonar plugins solves the issue.