QLocale::toDouble() gives unexpected result for same decimal and grouping symbol

It looks like if the same symbol (dot in this case), is used as the decimal symbol and the digit grouping symbol, then toDouble() gives different result with Qt5 and Qt6. For example, with the following code:

bool ok;
QLocale loc;
double number = loc.toDouble("0.003", &ok);
qDebug() << "LOCALE DOUBLE" << number << ok;

Qt5 outputs:

LOCALE DOUBLE 0.003 true

With Qt6 you get:

LOCALE DOUBLE 3 true