It appears you are trying this feature the same way it is defined in the documentation:
If you have confirmed that the label matches the project in the plan/instance, and have tried a browser refresh/cache clearing, it sounds like you may want to submit a support ticket to Atlassian. I see no open defects for this in the public backlog, so try adding one here:
Catch up with Atlassian Product Managers in our 2020 Demo Den round-up! From Advanced Roadmaps to Code in Jira to Next-Gen Workflows, check out the videos below to help up-level your work in the new ...
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event