Hi,
If You have activated these outcomes - are You testing them correctly?
Try to go to invoice in EDIT step to block it and then run Your WF for the same document of course - it should raise temporary exception and go to path d) Parked document blocked & & &
You can see this in WF log.
If it won't work like this - You can try to debug this method to check if exceptions are raised as expected.
br,
artur