After resolving and reopening a ticket, you realize that the initial resolution date has been updated. The only way to see when this was first resolved is by accessing the history tab in your issue.
The Resolution timestamp is automatically updated when there is an update to the Resolution field.
Install JIRA Suite Utilities so that we have access to the extra conditions and post functions we need for your workflow.
JIRA Cloud Instances can Enable the JIRA Suite Utilities by going to JIRA Administration > Add-ons > Manage Add-ons > search for "JIRA Suite Utilities" and click Enable (keyboard shortcut: g+g > Manage Add-ons)
Create a new Custom Field using the "Text Field (single line)" option, we called this "First Resolution Date," and make sure it is on the appropriate screens. Ideally we would want to use a Date/Time field, but it seems that JIRA Suite utilities is not able to condition on date fields at this time.
Copy and Edit your Workflow and create a New Transition that is basically the "Resolve Issue" transition but has a condition that checks to make sure that "First Resolution Date" field is null. This will ensure that this transition only shows up when the First Resolution Date has not already been set.
The New Transition name cannot have the same name as another Transition
For Example: if your "Resolve" Transition is between "In Progress > Done," create a new "Resolve Issue" Transition along the same "In Progress > Done" path
Once the condition is set, then create a post function for this transition that updates "First Resolution Date" to grab the current time (variable: %%CURRENT_DATETIME%%).
Update the "Fire a Generic Event event that can be processed by the listeners." Post Function to be the Issue Resolved event instead (this should ensure that the Resolution date field is updated as well).