There were 5 pageLoaded Popups events logged Sunday, 4th June 2017. This is drastically low.
This is an instance of the late subscriber problem.
As I suggested in T158999#3087132 and T158999#3110621, rely on [the event. mw.track protocol defined by the EventLogging extension](https://github.com/wikimedia/mediawiki-extensions-EventLogging/blob/master/modules/ext.eventLogging.subscriber.js) over the mw.eventLog.Schema class/API.