Ok, I figured out why the task wasn't starting, which was a simple matter of me forgetting to do start task > waiting or currently working for the scheduled machine. It's still failing on the OSDeploy almost instantly though, and I'm not sure how to even go about troubleshooting it.
Check the Scheduler and Inventory services are running on the Core.
Are you sure there are no historical Provisioning tasks still active for that machine or machines... First thing to check.
You cannot run two provisioning tasks against the same machine the second will instantly fail.
If you do not have other tasks active then the other reasons i found for this are the Computer ID is corrupt. I found if i deleted the MAC Address \ Computer from Devices and ran again it would work.
Our problem ended up being that my computer was inadvertently moved out of my department's scope. So, the device existed but I could not access it. We moved it back into my scope and worked again.