Say an instance of ClassA is the parent of a QAbstractAnimation object, and Q_GLOBAL_STATIC is used to create an instance of ClassA. When the application is closed and the global static objects are deleted, if the animation is still running, the Q_ASSERT(runningLeafAnimations >= 0) in QUnifiedTimer::unregisterRunningAnimation() can fail.

This happens if the unifiedTimer global static in qabstractanimation.cpp is deleted before the ClassA global static. When the ClassA parent deletes its QAbstractAnimation child, QAbstractAnimation internally calls QUnifiedTimer::instance(), which creates a new QUnifiedTimer instance since the global static has already been deleted. Then it calls QUnifiedTimer::unregisterRunningAnimation(), and the assert failure is triggered because runningLeafAnimations has not been incremented for the new instance of QUnifiedTimer.

Attached is a small example.