After dealing with the known issues ie wasm, freezing displays,... I decided to uninstall the aircraft and the wasm folder which did not resolve my issues.
I then performed following:
1. Uninstalled all my local airports form the community folder.
2. Uninstalled the airplane and wasm folder.
3. I uninstalled the Inimanager completely.
4. Downloaded/install a fresh copy of the Inimanager
5. Installed local airports
6. Installed the airplane from the Inimanager
7. Reboot the pc and updated the GSX app.
I performed 5 flights of about 2.5h without any problems so far. I messed around in the mcdu without any crash or freezing. TOD was also working fine.
I could not bringing him down.
I also observed that set the pax number manually in simbrief resulted in a correct GSX upload in the loadsheet of the OFP.
In conclusion, I can only point to the reinstallation of a fresh copy of the INImanager that did the trick.
rgds,