QJsonObject negative values not display correctly in watchlist whereas QJsonValue is fine

When a negative number (-1) is stored on a QJsonObject, it does not display corectly in watch list window. The same value is stored in a plain QJsonValue object, it does display correctly in the watch list window. Printing the QJsonObject instance does print out the correct value.

SSCCE to reproduce issue

1. Code

`main.cpp`

#include <QCoreApplication>
#include <QJsonObject>
#include <QDebug>

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

QJsonValue v(-1);
qDebug()<<"v="<<v;

QJsonObject obj {

};
qDebug()<<"obj="<<obj;

return a.exec();
}

1. set a breakpoint on line 16:

return a.exec();

1. run in debug mode to the breakpoint and expand instance "obj" to see a value of 134217727 ( 0x7ffffff. log_2(134217727)= 26.99), whereas "v" simply has -1