I created an update that was guaranteed to fail to install on one device (hacked the update module used to return 1 under ArtifactInstall).
Then I created two Pauses, one after Download and one after Reboot. After the first Pause it looks as expected (all devices finishes download successfully). See the first screenshot
However, when i Continue, the one device fails Install as expected but it is shown as it fails Downloading (that bar changes from green to red). See the second screenshot, with explanations.