QMultiHash::equal_range crashes when called in a const member function

#include <QCoreApplication>
#include <QMultiHash>
#include <QTimer>

class C {
    QMultiHash<int, int> hash{};
public:
    void equalRange() const {
        hash.equal_range(1);
    }
};

int main(int argc, char *argv[]) {
    QCoreApplication a(argc, argv);

    C().equalRange();

    QTimer::singleShot(0, &a, &QCoreApplication::quit);
    return a.exec();
}

QT -= gui
CONFIG += c++11 console
CONFIG -= app_bundle
SOURCES += main.cpp

1 QHashPrivate::Data<QHashPrivate::MultiNode<int, int>>::find qhash.h  547  0x403aa8 
2 QMultiHash<int, int>::equal_range                           qhash.h  1852 0x4038f4 
3 C::equalRange                                               main.cpp 9    0x403dca 
4 main                                                        main.cpp 18   0x4015b3  

Thread 1 (Thread 5136.0xd7c):
#0  0x0000000000403aa8 in QHashPrivate::Data<QHashPrivate::MultiNode<int, int> >::find (this=0x0, key=@0x6afdbc: 1) at C:/Qt/6.0.0/mingw81_64/include/QtCore/qhash.h:547
        hash = 1701952752
        bucket = 4294967364
#1  0x00000000004038f4 in QMultiHash<int, int>::equal_range (this=0x6afe00, key=@0x6afdbc: 1) at C:/Qt/6.0.0/mingw81_64/include/QtCore/qhash.h:1852
        it = {d = 0x7740f0, bucket = 7011824}
        end = {d = 0x0, bucket = 1697151428}
#2  0x0000000000403dca in C::equalRange (this=0x6afe00) at ..\QSettings\main.cpp:9
No locals.
#3  0x00000000004015b3 in main (argc=1, argv=0x773fe0) at ..\QSettings\main.cpp:18
        a = <incomplete type>