QProcess::execute() stopped working on Android after Qt 5.9

This is most likely related to QTBUG-67093.

When I call something like

QProcess::execute("/system/bin/pm install -r -d /sdcard/update/app.apk");

it works perfectly fine on 5.9.6 and failing on 5.10.1 and 5.11.1 for no reason (all I get is "-2" as return code - no exceptions or errors in the log).