QSerialPort memory management issue

The "libqt5serialport5-dev" library behaves different than the one that comes with the 'run' installer. When converting my project from a QtCreator project to a CMake project segmentation faults started to happen and upon inspection it seemed to come from the QSerialPort library that was installed with "sudo apt install libqt5serialport5-dev".
The project works fina again when the local Qt CMake packages are linked instead of the system wide ones.