crtdbg dumps a memory leak when sf::Text::setOutlineThickness is used - c++

Question

Working with SFML 2.4.2 on Windows 7 64-bit version, I've noticed an issue with sf::Text::setOutlineThickness(float). Once it is used in the program, except for default value 0, crtdbg dumps a memory leak of various sizes of bytes but always the same amount. I believe this is related to the size of the string, if the text gets drawn, and if the parameter of setOutlineThickness is accepted, demonstrated here:
/// Initial set-up
sf::Text test;
test.setString("A");
// ... Set charactersize, font, fillcolor, etc ...
test.setOutlineThickness(1);
test.setOutlineColor(sf::Color::Black);
/// Make a drawcall for test later in the program
void Game::draw(sf::RenderTarget & target, sf::RenderStates states) const
{
target.draw(test, states);
}
This produces a leak:
{8601} normal block at 0x0000000005CA5C90, 60 bytes long.
Data: < > 03 00 07 00 0B 00 0F 00 13 00 17 00 1B 00 1F 00
{8600} normal block at 0x0000000005E03A20, 120 bytes long.
Data: < > 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01
{8599} normal block at 0x0000000005E2A680, 960 bytes long.
Data: < > 00 00 00 00 80 07 00 00 0D 01 00 00 80 07 00 00
{8598} normal block at 0x0000000005CA36B0, 72 bytes long.
Data: < h > F0 1A 9D 05 00 00 00 00 68 AE 83 DB FE 07 00 00
If test.setString("B");, there are still four blocks but the byte size differs, since the string uses another character:
68 bytes, 136 bytes, 1088 bytes, 72 bytes.
Finally if test.setString("AB");, there are 8 blocks with the expected sizes:
{8667} normal block at 0x0000000005C35D10, 68 bytes long.
Data: < > 03 00 07 00 0B 00 0F 00 13 00 17 00 1B 00 1F 00
{8666} normal block at 0x0000000005C61310, 136 bytes long.
Data: < > 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01
{8665} normal block at 0x000000000325CDE0, 1088 bytes long.
Data: < > 00 00 00 00 80 07 00 00 0D 01 00 00 80 07 00 00
{8664} normal block at 0x0000000005C340D0, 72 bytes long.
Data: < h > F0 1A 96 05 00 00 00 00 68 AE B5 DB FE 07 00 00
{8601} normal block at 0x0000000005C35C90, 60 bytes long.
Data: < > 03 00 07 00 0B 00 0F 00 13 00 17 00 1B 00 1F 00
{8600} normal block at 0x0000000005D93A20, 120 bytes long.
Data: < > 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01
{8599} normal block at 0x0000000005DBA680, 960 bytes long.
Data: < > 00 00 00 00 80 07 00 00 0D 01 00 00 80 07 00 00
{8598} normal block at 0x0000000005C336B0, 72 bytes long.
Data: < h > F0 1A 96 05 00 00 00 00 68 AE B5 DB FE 07 00 00
I use sf::Text as a private member of a class which should be destroyed with the class but that doesn't seem to be the case. What am I missing?
I use _CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);, is this a false positive?
Glancing at the function, sf::Text::setOutlineThickness, I don't see an issue here. A brief documentation.
Different leaks depending on the size of the string is more of a symptom really, it's the drawcall and non-default value on outline thickness that I'm clueless on.

Answer 1

Looks like there is a real leak in SFML, at Font.cpp#L561
It looks like this:
FT_Glyph_Stroke(&glyphDesc, stroker, false);
But according to the docu of FT_Glyph_Stroke, it should actually be this, so the source glyph is destroyed:
FT_Glyph_Stroke(&glyphDesc, stroker, true);