What could cause my application compatibility issues between x64 and x86 architectures? - visual-c++

Question

I'm working on a VC++ app, and my job is to correct some bugs in it, the code was mainly written by a student last year.
It is a graphical application that uses both SFML and TGUI.
It targets 32bits architectures but actually its only working well on x64 computers.
On a x64 , absolutly everything works perfectly , but on a 32-bits systems , the text displayed using sf:Text and sf:Font just prints black blocks after the first call to the function that sets sf:Text's string.
I know that code targeting 32bits systems should work fine on x64 , and that's why I am lost. I checked which system architecture I am targeting.
I am using compatibles , 32bits , last updated SFML and TGUi libraries.
I checked a billion times if I got the right dlls, include and lib paths . The linker > start property got all .lib that both sfml and tgui relies on.
I know that the Font is loaded, but I know that it doesn't stay set on the Text even if the variable containing the font isn't destroyed and that I have set the font on the text earlier.
This is how the font is loaded and associated with the text :
MainWindow.cpp :
Font& MainWindow::m_fontDisplayer = m_data.getFont_1();
//init displayer
m_data.getDisplayer().setFont(m_fontDisplayer);
m_data.setDisplayer("");
m_data.getDisplayer().setCharacterSize(54);
m_data.getDisplayer().setFillColor(Color(0, 0, 0, 255));
DataManager(m_data):
Font DataManager::m_font_1 = Font();
if (!m_font_1.loadFromFile("Ressources/font_1.ttf"))
{
printf("\nCould not find font_1.ttf font.");
}
void DataManager::setDisplayer(std::string s) {
if (m_displayer.getFont() == NULL) {
//m_displayer.setFont(m_font_1);
}
m_displayer.setString(s);
m_displayer.setPosition(sf::Vector2f(320 - m_displayer.getGlobalBounds().width,82));}
This function is the one that maked me say that the font isn't set to the Text after some time.(m_displayer is sf::Text)Because I have set a stop point at the commented line and that it is accessed even if setting the font is the first thing that i do. Actually , that "if" statement was only to check the stop point, It doesn't fix the problem (makes my app crash on 32bit), and it would be too long because sf:Font operations are really heavy.
What could possibly cause that compatibility issue between the two architectures?
To add to what i said , I'm sure that the only difference between the systems im testing on is the architecture and not windows version. I tried on multiple computers, and again , the problems only appaers on 32-bit computers.
Thanks to anyone that could explain and help me understand the problem.
EDIT : I cleared the text about Tgui issues as i solved them.