ListView not rendering some items when the attached model is inserting more rows than would fit into the view

If an attach AbstractItemModel to an QML ListView insert more rows (using beginInsertRows() and endInsertRows() than ListView can show immediately (i.e. without scrolling), later insertions of more rows doesn't let the new rows being rendered at all - leading to a visual empty space in the list view. When then scrolling or resizing the list view items suddenly appear.

Tracing shows that items are build and layout correctly, but simply not rendered (it seems).

Increasing the "cacheBuffer" property of ListView "fixes" the problem (until you insert even more rows in one go).

I've attach a small example App with a custom QAbstractItemModel + QML file demonstrating this. The contained README.md describes how to show it.