When using DelegateModelGroup to group items then when a created item which is set to not be included will trigger an assert

When using DelegateModelGroup to group items then when a created item which is set to not be included will trigger an assert. In the case of the example which is set up to have a DelegateModelGroup with a custom name (selected) and that is set to be included by default. Then when the items are added to that group on creation, then when it hits the delegate's onCompleted handler and it sets the DelegateModel.inSelected to false it will trigger the assert:

ASSERT: "index >=0 && index < count(group)" in file /Users/andy/dev/qt5.15/qtdeclarative/src/qmlmodels/qqmllistcompositor.cpp, line 365

If this is bypassed (in release mode) then when you replace one model with the other (as the example does when you press a key) then it does not remove all the entries in the list as a result. But I suspect that problem is connected to the fact that it is asserting before, so fixing that should solve this one.