https://github.com/mysensors/MySensors/pull/1562 switches to using libgpiod instead of the earlier interface. I have not tested it myself but it looks good.
Update and problem fixed!
For everybody that will encouter this, the problem was at the sensor side because of the folder of the sensor! We created some metal brackets for it and they where exactly the same diameter. The fact that the mount squeezed the sensor made it return the lowest value.
Just needed to adjust the hole and everything was ok!
@mvader Turn the time delay adjustment preset on your PIR module to the minimum.. Now try it.. You will not get a continuous output..Also, prepare the circuit using a long wire from the back to the sensor of your module.
@tnick STM32F1 2019.12.8 (stm32duino) is the version that was active when the latest MySensors release was made. Later versions may or may not work; nobody would know until they tried.
