TableViewItemDelegateLoader.qml throws TypeError with QQmlListProperty model

I'm using qt qml to write OpenGL debugging/performance tools for the Mesa project.

Lately, the Qt in Debian testing (5.12) throws many errors when rendering TableViews that use QQmlListProperty containers as the model:
 

  file:///usr/lib/x86_64-linux-gnu/qt5/qml/QtQuick/Controls/Private/o.qml:97: TypeError: Type error

The table renders correctly in spite of the errors.
Using a QML ListModel for data does not generate the same spurious output. However, it does emit a smaller number of errors, which can also be seen in the piles of TypeErrors:

Model size of -3 is less than 0

The product that is generating these errors has been stable for many years and is used by graphics developers to find OpenGL perf/rendering issues on Intel and Freedreno Linux platforms.

A tiny project to reproduce the bug:

https://gitlab.freedesktop.org/majanes/qmlhack

Repro Steps:

1. git clone https://gitlab.freedesktop.org/majanes/qmlhack
2. cd qmlhack
3. meson setup build
4. ninja -C build
5. ./build/hack

I can hack TableViewItemDelegateLoader to drop the hasOwnProperty call, which is triggering the noise for QObjectList models.

I understand that TableView has been re-written.  That version is not yet packaged in Debian.  Seems like an easy bug to fix.