The JMX attribute com.atlassian.jira/metrics is not consistent in Jira 8.20.X version

Issue Summary

The JMX attribute com.atlassian.jira/metrics is not consistent in Jira 8.20.X version

This is reproducible on Data Center: (yes) 

Steps to Reproduce

• Install Jira 8.20.6
• Open a client like JDK mission control and map to the running port
• Browse the attribute

Expected Results

It should list all the attributes for com.atlassian.jira/metrics

Actual Results

It is inconsistent. Sometimes, it doesn't load the values, sometimes it loads a few. Unlike higher versions (9.9, 9.7), where it loads all the attributes correctly, Jira 8.20 doesn't give a consistent picture

Workaround

No workaround available