Crash (SIGSEGV) in QPlatformWindow::window() when pressed on Qt::ToolTip window border

I have a Qt::ToolTip window which should show in a specific place, similar to Qt Creator's LocatorPopup. ( when you pressed cmd + k).

But the app receives SIGSEGV while trying to access QPlatformWindow::window() in qnsview_mouse.mm:

QRegion mask = m_platformWindow->window()->mask(); 

To reproduce this (in my case), a user should press on a specific place on the border of windows near Qt::ToolTip window border. See videos.

The issue not happened if I changed Qt::ToolTip to Qt::Popup. But this is not an option for me. 

Attached example and videos. (with Qt Creator steps and crash report)