[5.4 Regression] Fails to run example code with two Items with the same name registered by different plugins

The attached code runs just fine in Qt 5.3.2, i.e. the output is

TestA created
qml: Hello QSortFilterProxyModelQML(0x2001e30)

but if run under 5.4.0 i get

TestA created
qml: Hello null
main.qml:10:40 Unable to assign QSortFilterProxyModelQML to QSortFilterProxyModelQML