The same domain appears more than one time in the Domains Overview dashboard if the DMARC policy and/or percent of the emails to apply the policy to (the value used in the pct=tag) was changed after the record publication in DNS.
In this scenario, GlockApps shows the domain with the old policy/percent and the domain with the current policy/percent. The data is sorted by the total number of messages sent from the domain within the selected period in the descending order.
If no changes have been made to the DMARC policy or percent but there are two lines for the same domain in Domains Overview, typically this is explained by the missing pct= tag in DMARC reports.
The reporters have to include the percent of the messages to which the policy applies in the <policy_published> block in the report. When the reporter skips doing this, the default value of 100% is used.
GlockApps DMARC Analytics adds a new line for the same domain showing the 100% policy, which results in the same domain being listed more than one time in the Domains Overview dashboard.