Hi Ann,
The company’s core engineers upgraded our SonarQube Enterprise Edition server to version 2025.5 so I thought to try again to run a sonar scan with the latest version (which is 6.3.1.5724) of the SonarQube gradle plugin. The scan succeeded so there were no more errors thrown during the scanning.
So, from my point of view, this ticket can be closed.
Thank you so, so much for your support! 
/Cornel