Multiple ListModel related issues and crashes

This is with QML compiled from qt/qt-qml repo with HEAD at
672e06aef096d3e7a81826b28121f3314948eeff and tesla HEAD at
4849e8085c00905d2b7b309006bf8ce87042c507

In tesla/appLauncher/AppList.qml change line 48 from
model: 3
to
model: launcherPages
then run tesla. Open the launcher page and (issue 1) note that none of the three page indicators
at the top is highlighted. Scroll horizontally to the last page, and (issue 2) note how the page gets
stuck when trying to scroll further (same thing happens when scrolling left of the first page).
Now change either "3" on line 38 or 48 to "4", and run tesla again. Scroll past the end of the
launcher pages list and (issue 3) note how the QML viewer crash with the following message in
the console:
ASSERT: "!create" in file qml/qdeclarativedeclarativedata_p.h, line 120
The same crash (issue 4) also happens if pressing Ctrl+R to reload the QML application, even
with fewer than 4 pages.