Android: [Reg 5.5 -> 5.6] Crash when getting back to Qt app on Samsung XCover 3 (SM-G388F, Android 5.1.1)

Some hundred of our app users have specific device (Samsung SM-G388F (XCover 3, first edition - with Android 5.1.1)), and experience that about every second time they return to the Qt app, the app crashes. This has been ok until we shipped the app using Qt 5.6.0 for Android.

Please note that the Samsung XCover 3 also has an upgraded version (SCM-G389F), that is in stores now. As far as I know, the only difference here is that this is shipped with Android 6.0. To my knowledge, users with this device do not have this issue.

Please take a look at the following video:
https://www.dropbox.com/s/o3w5q0dusmixtud/20160819_141756.mp4?dl=0 

Attached is adb log and application output from Qt Creator when running the attached simple helloworld with a button for opening a link.

How to reproduce:

1. Open the attached app using Qt 5.6 or newer on a Samsung SM-G388F device
2. Push the "open link" button to open some other app (web browser in this case, but it could be phone app, camera, gallery or anything)
3. Push back button to get back to the Qt app
4. If no crash, repeat.

I have tested both with and without this line at the top of main() in main.cpp:
qputenv("QT_BLOCK_EVENT_LOOPS_WHEN_SUSPENDED", "0");

Qt 5.4.2: works fine
Qt 5.5.1: works fine
Qt 5.6.0: does not work
Qt 5.6.2 from git sources: does not work
Qt 5.7.0: does not work