Which version of mraa are you using? I'm going to test your script with my Edison+Arduino Expansion Board (I don't have access to a GPIO block) and see if I get the same behavior.
Hi Peter. `mraa.getVersion()` in python returns `v0.7.2`.
I think however I've found the culprit - `pin.isrExit()` seems to hang the script, which prevents the process from ending and a fresh working one from starting up. Commenting it out seems to work.