The same person, two leads, two reps.

Why it happens

• A duplicate rule that allows the save, with an alert, lets the second lead through. Then it is routed.
• Duplicate rules run before assignment rules. They only stop a record if they are set to block it.
• Assignment rules look at the new lead. They do not look up who owns the match.
• A web form and a list import often create the same person within minutes.

Where to fix it

• Block or merge at creation where you can.
• Where you cannot, route the new lead to the owner of the match, with a lookup before the rule. See routing to the account owner.
• Check who owns the record after a merge. See merged duplicate leads.

Count it yourself

SELECT Email, COUNT(Id) FROM Lead WHERE IsConverted = false AND Email != null AND CreatedDate = LAST_N_DAYS:30 GROUP BY Email HAVING COUNT(Id) > 1

Open a few of the emails and compare the owners. Different owners on the same email is this problem. The wider picture is in duplicate leads in Salesforce.

The free scan cannot count duplicate leads. It checks the setup behind it.

Decide who keeps it

Pick one rule before you merge. Write it down.

• The owner of the account, if the lead matches one.
• Otherwise the owner of the older record.
• Otherwise the rep who has logged activity.

List the owners behind a few duplicate emails first.

SELECT Email, OwnerId, CreatedDate FROM Lead WHERE Email IN ('a@example.com', 'b@example.com') ORDER BY Email, CreatedDate

A worked example

A made-up pair: two leads for one person, created four minutes apart. Priya holds the first and Sam holds the second. The company already exists as an account, owned by Lee.

Under the rule above, Lee keeps it, because the account has an owner. Merge into one record, move the owner to Lee, and tell Priya and Sam.

Steps

1. Count the duplicate emails with different owners.
2. Apply the rule to each pair.
3. Merge, then check the owner after the merge.
4. Fix the entry point so the second one stops arriving.