I wonder if it was a failed install of some python packages that get downloaded from PyPI on startup for this extension. As seen in the code below it will download networkx at startup which also requires getting the dependent decorator module.
The extension should probably be updated to get these packages at build time like how SlicerRadiomics gets some python packages during the build process to package with the extension. Described in Install python library with extension or here. @James_Hoctor or @bpaniagua , it looks like you’ve been doing some maintenance on this extension. You might want to implement this change in the build process.
@crisandr Maybe try using PythonSlicer.exe which is found in your Slicer installation to uninstall/reinstall the packages or clear out any failed downloads in a cached location. Did you install Slicer into a writeable location where the use of slicer.util.pip_install("networkx") would succeed when using the python interactor in Slicer?