The title pretty much says it all. I'm getting an 'Unauthorized' response when I try to /breakroleinheritance on a Tasks list item in a 2013 workflow (inside an App Step). The strange thing is that I can run the command successfully in Fiddler, and I can /breakroleinheritance on items of other list types in 2013 workflows with no problem. I've tried the command in both an App Step and outside of an App Step, while kicking off the workflow with a site collection admin user - both with the same result.
Client is in O365. Is this just one of those non-documented oddities about Tasks? I would be super grateful if someone could try and duplicate this behavior and let me know how they fare.