We tried to update from Qt 6.7.2 to 6.8.0 and an integration test fails on macOS. We have an SDK that spawns a separate thread for QCoreApplication. After the application triggers a shutdown of the SDK the whole QCoreApplication and the corresponding QThread will be terminated.
This works with Qt 6.7.x without problems. Also this works without Qt 6.8.0 on Linux without problem. But the same integration test will fail with Qt 6.8.0 and macOS.

I stripped out the integration test into a reproducer project in the attachment.
On macOS it will print out this lines that indicates that there are still living QObjects. Looks like the QThread will be removed later now.

 = QThread(0x600001d88020): Qt MainThread
There are zombies behind you: 1
 < QObject(0x600001d88020): Qt MainThread