Alias is invalid when accessed from C++ via QObject::property()

23:07:31: Starting /Users/mitch/dev/temp/qmlanimation-qt_dev_debug_non_fw-Debug/tst_untitled...
QML debugging is enabled. Only use this in a safe environment.
********* Start testing of tst_untitled *********
Config: Using QtTest library 6.5.0, Qt 6.5.0 (arm64-little_endian-lp64 shared (dynamic) debug build; by Apple LLVM 13.1.6 (clang-1316.0.21.2.5)), macos 12.4
PASS   : tst_untitled::initTestCase()
QDEBUG : tst_untitled::testCase1() QQuickItem_QML_1(0x10a07d7c0, parent=0x0, geometry=0,0 0x0) QVariant(Invalid)
FAIL!  : tst_untitled::testCase1() 'derived' returned FALSE. ()
   Loc: [/Users/mitch/dev/temp/qmlanimation/tst_untitled.cpp(65)]
PASS   : tst_untitled::cleanupTestCase()
Totals: 2 passed, 1 failed, 0 skipped, 0 blacklisted, 78ms
********* Finished testing of tst_untitled *********
23:07:32: /Users/mitch/dev/temp/qmlanimation-qt_dev_debug_non_fw-Debug/tst_untitled exited with code 1