Using JIRA Automation Plugin to close an Issue will result in an unresolved closed issue
Please note that JIRA Automation Plugin is an unsupported add-on. As such is not supported by Atlassian Support.
Problem
When you create a rule in JIRA Automation Plugin to close a ticket when a certain condition is met. Once this condition is met, then the issue is successfully close, however, the resolution is not set.
Cause
This is because in the workflow of that issue, the resolution value is given from a resolution screen. However, using the automation this screen is not displayed, therefore the resolution field is not specified and the issue is closed without a resolution.
Resolution
Specify a resolution of the Transition Fields column, Eg: resolution=4, where 4 is the ID for resolution Incomplete. The easiest way to find the ID of resolution is to go to the resolution page. Then click on the edit link of the resolution to find the ID.
For an example of how this rule will look in JIRA Automation plugin: