subprocess locking up grasshopper after completed

I am opening an executable to run an operation via subprocess module.

It completes successfully without locking up if you use the "test" button within the editor,but outside just running it as a component..it freezes up, only allow zooming in and zooming out. panning or clicking on components fails afterward and I am forced to reload grasshopper. Is this a bug or am i doing something wrong?

below is my supprocess (I am running "convert.exe" from imagemagick standalone)

p1 = subprocess.Popen(args,stdout=subprocess.PIPE,  creationflags=DETACHED_PROCESS).wait()