How to explain differences between Jacoco report and Sonarqube dashboard?

Oh yes, I can’t agree more, but your jacoco import plugin needs this to work sadly :

" the JaCoCo plugin imports coverage reports module by module, so we need to import the same report multiple times (once for every module) to have coverage for all modules. To achieve this we set the property sonar.coverage.jacoco.xmlReportPaths in every module"

source : [Coverage & Test Data] Importing JaCoCo coverage report in XML format