QtLocation examples Places (QML) and Map Viewer (QML) exception

Both Qt example codes Places (QML) and Map Viewer (QML) are crashing with exception:

"Exception at 0x0, code: 0xc0000005: write access violation at: 0x0".

Both example code applications show the geographic map and even zooming in and out or changing the MapType (Street, Cycle, Tansit, Terrain Map etc.) works fine. But clicking on following menu entries does lead to crash the application:

Places (QML):

1. Searching for a place.
2. Clicking on any 'Settings' menu entry.

Map Viewer (QML):

1. Clicking on menu Provider: here or mapbox (esri and osm work fine)
2. Clicking on any 'Tools' menu entry.

This is a regression that took place in Qt 5.12.3! Using any prior Qt versions both example codes run fine. (Tested Qt 5.9.7, Qt 5.9.8, Qt 5.11.3, Qt 5.12.0, Qt 5.12.1, Qt 5.12.2 prebuild binaries with working OpenSSL 1.0.2r-win64 installed).

The exception happens inside the file stackView.qml and its function stackView.push(). Inside stackView.push() is a function __performTransition() and in this function calling the function __loadElement() does cause the exception.

Both QtLocation and QML are completely new to me. So I'm not able to say if this is a QtLocation or an QML bug.