QInputMethod visibleChanged signal fired incorrectly on Android

We are working on a pure openGL based mobile application (using QOpenGLWindow). We have no widgets or QML and we therefore need to handle user input ourselves. Qt provides QInputMethod for this purpose and it works very well, except in one problematic situation.

If our application is started immediately after the phone is booted, when we show the keyboard the visibleChanged signal fires multpiple times and QInputMethod::isVisible() returns true and then false. This only happens the very first time the keyboard is shown. The false visibility signal is completely spurious.

It is a problem for our app because we follow the state of the keyboard in order to display the correct controls to the user. If we receive false for the visibility we expect that this is because the user has manually hidden the keyboard (by pressing the back button).

The problem is easy to reproduce with some simple code. Create a Qt Console application. Modify the .pro file to include the gui component (instead of excluding it) and modify main.cpp (see attachments)

The debug output shows the following:
1st time (immediately after phone has booted):
Note spurious false / true messages
W libKeyboardTest.so: (null):0 ((null)): show keyboard
W libKeyboardTest.so: (null):0 ((null)): QObject::connect: No such signal TestWindow::cursorPositionChanged()
W IInputConnectionWrapper: getCursorCapsMode on inactive InputConnection
W IInputConnectionWrapper: getCursorCapsMode on inactive InputConnection
W libKeyboardTest.so: (null):0 ((null)): keyboard Visibility changed: true
W libKeyboardTest.so: (null):0 ((null)): keyboard Visibility changed: false
W libKeyboardTest.so: (null):0 ((null)): QMetaObject::invokeMethod: No such method TestWindow::inputMethodQuery(Qt::InputMethodQuery,QVariant)
D ViewRootImpl: MSG_RESIZED: ci=Rect(0, 96 - 0, 0) vi=Rect(0, 96 - 0, 1128) or=1
W libKeyboardTest.so: (null):0 ((null)): keyboard Visibility changed: true
W libKeyboardTest.so: (null):0 ((null)): QMetaObject::invokeMethod: No such method TestWindow::inputMethodQuery(Qt::InputMethodQuery,QVariant)
V ActivityThread: updateVisibility : ActivityRecord{d3ef4e6 token=android.os.BinderProxy@92bdaf4 {org.qtproject.example.KeyboardTest/org.qtproject.qt5.android.bindings.QtActivity}} show : true

Any other time (correct behaviour):
W libKeyboardTest.so: (null):0 ((null)): show keyboard
W libKeyboardTest.so: (null):0 ((null)): QObject::connect: No such signal TestWindow::cursorPositionChanged()
W IInputConnectionWrapper: getCursorCapsMode on inactive InputConnection
W libKeyboardTest.so: (null):0 ((null)): keyboard Visibility changed: true
W libKeyboardTest.so: (null):0 ((null)): QMetaObject::invokeMethod: No such method TestWindow::inputMethodQuery(Qt::InputMethodQuery,QVariant)
D ViewRootImpl: MSG_RESIZED: ci=Rect(0, 96 - 0, 0) vi=Rect(0, 96 - 0, 1128) or=1
W libKeyboardTest.so: (null):0 ((null)): QMetaObject::invokeMethod: No such method TestWindow::inputMethodQuery(Qt::InputMethodQuery,QVariant)

In our real application we have provided the missing cursorPositionChanged signal and inputMethodQuery(), so the visibility issue has nothing to do with that. Please can you investigate what is happening. Perhaps there is some uninitialised variable somewhere?