Why do rules never act on one particular space?
Because your Atlassian organisation applies a data security policy that blocks app access to that space, so the app cannot reach its work items at all.
Rules scoped to that space and rules scoped to all spaces both leave it untouched, and an organisation admin has to change the policy.
Related pages
Restricting Out of Office to Specific Spaces - where this is covered in full.
Troubleshooting - more questions on this topic.