Strange QHash crash

[t_3]

precondition:

static QHash<SomeQObject *, QString> s_register;
 
SomeQObject::~SomeQObject()
{
    s_register.remove(this);
}

static QHash<SomeQObject *, QString> s_register;

SomeQObject::~SomeQObject()
{
    s_register.remove(this);
}

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if the deconstructor is called during program shutdown there happens a crash in the QHash detach helper (in line 10); the object is valid at the time when "remove" is called, but the key below is now apparently a null pointer...

template <class Key, class T>
struct QHashNode
{
    QHashNode *next;
    uint h;
    Key key;
    T value;
 
    inline QHashNode(const Key &key0) : key(key0) {} // ### remove in 5.0
    inline QHashNode(const Key &key0, const T &value0) : key(key0), value(value0) {}
    inline bool same_key(uint h0, const Key &key0) { return h0 == h && key0 == key; }
};

template <class Key, class T>
struct QHashNode
{
    QHashNode *next;
    uint h;
    Key key;
    T value;

    inline QHashNode(const Key &key0) : key(key0) {} // ### remove in 5.0
    inline QHashNode(const Key &key0, const T &value0) : key(key0), value(value0) {}
    inline bool same_key(uint h0, const Key &key0) { return h0 == h && key0 == key; }
};

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this crash happens not when the deconstructor is explicitly called otherwise, it also does not happen if i use a QMap instead a QHash (what is not a big problem fortunately) - any ideas what may cause this???