Summary

To obtain the number of times the status (count) of an issue (Bug) has been changed to "Re-opened"

Environment

Jira Cloud

Solution

Here is an automation rule example of achieving the requirement:

Trigger: When the Issue transitioned to Reopened.

Condition:  Issue type equals Bug

Action: Log action: Add value to the audit log
                 → Log message : {{#increment}}{{issue.Number1}}+1{{/}}

             Edit Issue for custom field Number1 with smart value {{#increment}}{{issue.Number1}}+1{{/}} 

Snippets of the above automation rule for reference: