Pointeurs changent de valeur 'seuls'

void ReceiptSection::createLines (std::vector<std::vector<cv::Rect*> >& lines, cv::Rect& currentLetter)
{
     lines.push_back( std::vector<cv::Rect*>());
     std::vector<cv::Rect*>& newLine = lines.back();
     newLine.push_back(&currentLetter);
     LOG("---------------- PTR lines.back : " << &(lines.back()), 3);
     cv::rectangle(_sectionImage, cv::Point(currentLetter.x, currentLetter.y), cv::Point(currentLetter.x+currentLetter.width, currentLetter.y + currentLetter.height), cv::Scalar(0), 2);
}

void ReceiptSection::main()
{
    std::vector<std::vector<cv::Rect*> > lines;

    // _extractedLetters est un attribut de ma classe correctement rempli
    // std::vector<cv::Rect> _extractedLetters;
    std::vector<cv::Rect>::iterator aLetterIt = _extractedLetters.begin();

    do
    {
	LOG("---------------- Before createLines", 3);
	displayLinesPtr(lines);

	createLines(lines, *aLetterIt);

	LOG("---------------- After createLines", 3);
	displayLinesPtr(lines);
		
	aLetterIt++;
   }
   while (aLetterIt != _extractedLetters.end());

void ReceiptSection::displayLinesPtr(const std::vector<std::vector<cv::Rect*> >& lines)
{
    LOG("----------------------------LinesPtr---------------------------", 3);
		
    int cpt=1;
		
    for(std::vector<std::vector<cv::Rect*> >::const_iterator lineIt=lines.begin(); lineIt!=lines.end(); ++lineIt, cpt++)
    {
    	LOG("ptrLines " << cpt << " = " << &(*lineIt), 3);
    }

    LOG("---------------------------------------------------------------", 3);
}

 ---------------- Before createLines
 ----------------------------LinesPtr---------------------------
 ---------------------------------------------------------------
 ---------------- PTR lines.back : 0x10115aa50

 ---------------- After createLines
 ----------------------------LinesPtr---------------------------
 ptrLines 1 = 0x10115aa50
 ---------------------------------------------------------------

 ---------------- Before createLines
 ----------------------------LinesPtr---------------------------
 ptrLines 1 = 0x10115aa50
 ---------------------------------------------------------------
 ---------------- PTR lines.back : 0x10115a838

 ---------------- After createLines
 ----------------------------LinesPtr---------------------------
 ptrLines 1 = 0x10115a820
 ptrLines 2 = 0x10115a838
 ---------------------------------------------------------------