The most reliable method to report on auto merged tickets is to tag them with something like closed_by_automerge using a Zendesk trigger. You can then report on the tag in Explore.
Here's a sample trigger to tag tickets that were closed by Auto Merge:
Trigger name
Auto Merge: Tag Merged Ticket
Trigger category
(choose a category)
Conditions
──────────────────────────────────────
Meet ALL of the following conditions
Category Operator Value
[ Status ] › [ Is ] › [ Closed ]
[ Comment text ] › [ Contains the following string ] › [ This request was closed and auto merged into request ]
Actions
──────────────────────────────────────
Category Value
[ Add tags ] › [ closed_by_automerge ]
You can also tag the target ticket (the active ticket) with a trigger:
Trigger name
Auto Merge: Tag Target Ticket
Trigger category
(choose a category)
Conditions
──────────────────────────────────────
Meet ALL of the following conditions
Category Operator Value
[ Ticket ] › [ Is ] › [ Updated ]
[ Comment text ] › [ Contains the following string ] › [ was closed and auto merged into this request. Last comment in request ]
Actions
──────────────────────────────────────
Category Value
[ Add tags ] › [ automerged ]
Tracking auto merged tickets prior to your trigger
To track tickets that were already auto merged prior to creating the trigger, you can use the following searches in Zendesk:
"was closed and auto merged into this request" order_by:updated_at sort:descOR
"This request was closed and auto merged into request" order_by:updated_at sort:desc