App.open doesn't work with variable passed on command line

I have a script that opens an app with parameters. When I run it from the ide with a fixed command, it works perfectly.

cmd = "c:/path_to_exe/myapp.exe -- --param1 param1 --param2 param2"
App.open(cmd)

If I try running my script with parameters passed on the command line, it doesn't open the application.

java -jar sikulix-2.0.1.jar -r man-1 --args "c:/path_to_exe/myapp.exe -- --param1 param1 --param2 param2"

import sys
cmd = sys.argv[1]
App.open(cmd)

What am I doing wrong? I've tried several combinations of quotes etc., and while the cmd variable prints out correctly, it does nothing, not even give an error.