SonarQube 4.5 does not populate technical debt with mysql datasource - maven

Question

I mvn sonar:sonar a project and problems with our code is recorded in the technical debt in sonarqube when we use the default database - i.e. default install of version 4.5. It works, out of the box:
Blocker 0
Critical 0
Major 88
Minor 70
Info 12
I change the datasource to mysql and
Blocker 0
Critical 0
Major 0
Minor 0
Info 0
is recorded. No errors presented by mvn or sonar. I can see all drivers load during mvn run.
In .m2/settings.xml I have
<profile>
<id>sonar</id>
<activation>
<activeByDefault>true</activeByDefault>
</activation>
<properties>
<sonar.jdbc.url>
jdbc:mysql://sonar.company.io:3306/sonar?useUnicode=true&characterEncoding=utf8
</sonar.jdbc.url>
<sonar.jdbc.username>sonar</sonar.jdbc.username>
<sonar.jdbc.password>pass</sonar.jdbc.password>
<sonar.host.url>
http://sonar.company.io:9000
</sonar.host.url>
<sonar.verbose>true</sonar.verbose>
</properties>
</profile>
I can am able to connect via the hostname using mysql -usonar -ppass -h sonar.company.io and there is content in the database.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| sonar |
mysql> show table status;
+---------------------------+--------+---------+------------+-------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------+----------+----------------+---------+
| Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time | Update_time | Check_time | Collation | Checksum | Create_options | Comment |
+---------------------------+--------+---------+------------+-------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+-------------+------------+-----------+----------+----------------+---------+
| action_plans | InnoDB | 10 | Compact | 0 | 0 | 16384 | 0 | 16384 | 4194304 | 1 | 2014-09-30 14:30:17 | NULL | NULL | utf8_bin | NULL | | |
| active_dashboards | InnoDB | 10 | Compact | 5 | 3276 | 16384 | 0 | 32768 | 4194304 | 6 | 2014-09-30 14:30:10 | NULL | NULL | utf8_bin | NULL | | |
| active_rule_parameters | InnoDB | 10 | Compact | 42 | 390 | 16384 | 0 | 0 | 4194304 | 43 | 2014-09-30 14:30:16 | NULL | NULL | utf8_bin | NULL | | |
| active_rules | InnoDB | 10 | Compact | 1099 | 74 | 81920 | 0 | 49152 | 4194304 | 992 | 2014-09-30 14:30:18 | NULL | NULL | utf8_bin | NULL | | |
What could be the reason?