Media search extension was enabled in Portuguese Wikinews (T299872), and have officially made MediaSearch the default search on their wiki (https://pt.wikinews.org/w/index.php?search=tree&title=Especial:MediaSearch&type=page).
We did some test searches on PT Wiki News and also on Commons with console event logging turned on, and I only see the events show up properly on Commons. We also checked the event.eventgate_analytics_external_error_validation table in the Data Lake, and the corresponding Kibana dashboard, and didn’t see MediaSearch show up there either.