To track changes in your Smart Checklist you need to:

• switch to the Activity tab of your Jira issue 

• select the "Smart Checklist History" tab

"Smart Checklist History" tab tracks these list of changes:

Changes in the Smart Checklist	Changes in "Smart Checklist History" tab
Adding checklist item
Deleting checklist item
Checklist item update
Status change
Checklist item movement
Checklist replacement
Saved as a template
Import template