Roll back a driver or 2 might be an idea. I am on the 18.2.1 driver & stepsons R7360OC same driver. Are you using any 3rd party software like Msi Afterburner, Rivatuner anything like that idea would be uninstall all that junk. With wattman you should be able to control how you bump it. I only run voltage bumped & increased fan profile I could suggest run it like that before giving it an OC is it. Is your card the proper OC card hard to say a bit more info may be handy of your build could be PSU related to.
I tried using MSI Afterburner, and I discovered this issue, but with AMD Center built-in OverDrive it's the same. It was the same on 18.2.1 driver. Before, I was using 17.. something driver version and it was overclocked without a problem.