When you run a deployment and one of the steps fails, this is correctly shown in the UI.
The problem is when you run another deployment of the same version, believing the issue was occational. Then the second run will skip the previously failed step, stating that the step is skipped, because it is already run (which is correct, but it did fail).
The UI then shows green lights, and the user believes everything was ok, which it is was - the package was never installed.
I use the Octopus version 188.8.131.525, so I do not know if this has been fixed, but I could not find the issue in the change log.