Hey Doug,
Welcome in this forum, and thank you for reaching out!
We are slowly moving away from the support of exec format, as it has many drawbacks, in profit of the XML format. For this, we now provide the dedicated JaCoCo plugin.
Before digging to much into the configuration of JaCoCO (or your analysis), did you try to produce XML reports instead of exec ? If not, could you give it a try?
It will also be easier for you to check that the content of the XML report is correct, and consequently potentially identify some JaCoCo misconfiguration.
Note that you will have to change the property to be used to sonar.coverage.jacoco.xmlReportPaths (instead of sonar.jacoco.reportPaths).
Regards,
Michael