Object is being invalidated and losing its parent. See Efl.Object.invalidate.

Since 1.22

invalidate @hot;

EFL_EVENT_INVALIDATE(void, @hot)

static void
on_efl_event_invalidate(void *data, const Efl_Event *event)
{
    void info = event->info;
    Eo *obj = event->object;
    Data *d = data;
 
    /* event hander code */
}
 
static void
setup_event_handler(Eo *obj, Data *d)
{
    efl_event_callback_add(obj, EFL_EVENT_INVALIDATE, on_efl_event_invalidate, d);
}