prism central deployment hung

My download for prism central appears to have failed, but the task is still hung at 100% with no apparent way to clear it out or force it to try a re-download. acli task.list shows the child task failed:

bff159bd-a62e-49d4-a52e-e73363796abf f78b4c99-8a15-479e-9ef4-23207c243456 cluster_config 2 kDownload kFailed
f78b4c99-8a15-479e-9ef4-23207c243456 cluster_config 1 kPrismCentralDeploymentRequest kRunning

Is there some way to either nuke the original task for force it to re-try the download? task.cancel succeeds but doesn't actually cancel the task.