QtQuick Shape crashes on Windows / blocks GUI on Linux

We currently try to display a roadmap of a virtual simulation database in QtQuick. We don't need any geo-referencing. But we have a lot of lines (about 40000 polylines containing 1 Mio vertices in one map layer).

Because I didn't find anything better so far, I use a QML Shape. According to the documentation one Shape is better than many. Therefore I tried to use a Shape per map layer. In order not to block the GUI thread I set the Shape's asynchronous flag to true.

I did this first on Linux (Qt 6.5.2) then compiled the same application on Windows (Qt 6.5.3):

On Linux: The moment I set the data property of the Shape the GUI is blocked for about 30 seconds. Which should not happen if asynchronous is set, as far as I understand the manual.
On Windows: The application crashes with an infinite recursion. See attached screenshot.

To reproduce this I made a small application which creates 40000 parallel polylines (with coordinates all within 0 <= X < 11000 and  0 <= Y < 14000). See attached zip file.