`QObject::startTimer` triggers a call to a GGlobalStatic when it is no longer valid and causes application to crash

I'm debugging a popular application[1] crash when running under Wayland/FlatPak. And I've traced the problem down to Qt I think.

There are 23 threads at the moment of the crash. All but one of them are blocked at a poll() or pthread_cond_wait().

The crashing thread's backtrace is this: https://pastebin.com/An9wDXM2

Examining the backtrace, I get to know that QObject::startTimer() will trigger a call to QAbstractEventDispatcherPrivate::allocateTimerId() whose body is:

{
    return timerIdFreeList()->next();
}

timerIdFreeList() returns the NULL and causes the app to crash. timerIdFreeList is declared as:

typedef QFreeList<void, QtTimerIdFreeListConstants> QtTimerIdFreeList;
Q_GLOBAL_STATIC(QtTimerIdFreeList, timerIdFreeList)

Taking a look at Q_GLOBAL_STATIC, I've got the impression that it should never return NULL as long as the application doesn't exit. Maybe the application was already on some exit-cycle and stange shutdown order led to this issue. I'd like hints on how to proceed to debug this issue.

[1] Telegram Desktop