The trigger suppression rule for a popup campaign works with buttons that don't track conversions. The instances in which conversions aren't tracked are:
The visitor clicks on the campaign's default close icon to opt out of the popup. Head to this article to learn how to edit the default close icon →
When using an alternative close button, the "Disable conversion tracking" needs to be enabled for the suppression rule to work:
If a button is set to redirect the visitor to another URL or campaign, then the suppression rule won’t work. We suggest using a targeting condition if the popup should only be seen by visitors who haven’t converted with it.