This seems like a new issue in the 6.9 timeframe. Any time there's class with the same name as the enclosing namespace, lupdate reports a missing `Q_OBJECT` macro error even though the class does mention `Q_OBJECT`. Minimal sample code looks like:

#include <QObject>

namespace Test {
class Test : public QObject {
  Q_OBJECT

public:
  Test();
};

Test::Test() {
  setObjectName(tr("Test"));
}
}

Running lupdate on this produces:

$ ~/Qt/6.9.2/macos/bin/lupdate test.cpp
lupdate warning: no TS files specified. Only diagnostics will be produced.
test.cpp:12: Class 'Test' lacks Q_OBJECT macro

Moving the call to `tr` inline or changing either the class or namespace name avoids the issue.