The below is from Ovie in the Splunk community Slack channel #enterprise-security: Not sure if it is your issue but it is supposed to be related to duplicates like that. So it might apply to some of you.
This can happen because of phased_execution_mode
https://docs.splunk.com/Documentation/ES/5.2.0/RN/KnownIssues
2019-04-08 SOLNESS-18603 Incident Review: eventCount does not match resultCount causing display issues (such as events being displayed twice)
Workaround:
Set phased_execution_mode to singlethreaded
For: limits.conf
[search]
phased_execution_mode = singlethreaded
https://docs.splunk.com/Documentation/ES/5.1.0/Install/DeploymentPlanning#Splunk_Enterprise_system_requirements
Splunk Enterprise Security 5.1 is compatible with Splunk Enterprise 7.1.0 and 7.1.1 only by setting phased_execution_mode=singlethreaded in the [search] stanza of the $SPLUNK_HOME/etc/system/local/limits.conf file to avoid an issue that is fixed in Splunk Enterprise 7.1.2. However, if you apply this workaround for 7.1.0 and 7.1.1 and then upgrade Splunk Enterprise but remain on ES 5.1, then you need to set it back to phased_execution_mode=multithreaded.
Splunk Enterprise Security 5.2.x is compatible with Splunk Enterprise 7.1.0 and 7.1.1 only by setting phased_execution_mode=singlethreaded in the [search] stanza of the $SPLUNK_HOME/etc/system/local/limits.conf file to avoid an issue that is fixed in Splunk Enterprise 7.1.2.
Bottom line is this setting has caused some serious grief.
... View more