@groothuyse confirmed that they are using the JaCoCo .exec format for their coverage reports.
We deployed an update to our Java analyzer today, and that included the following ticket: https://jira.sonarsource.com/browse/MMF-1651 where we dropped support for importing the jacoco.exec coverage reports.
The following reason is given:
We know that the .exec file is not an exchange format. This is an internal format used by JaCoCo developers. It is not at all recommended to use it for integration purpose.
Because of that, we want to get rid of the support of the .exec file format and rely only on the XML one.
This feature has been deprecated for quite some time, and warnings should have been reported in the SonarCloud UI.
Switching to the Jacoco XML format should fix your issues.
Tom