@Gargron hey, thanks for the clarification. I found the reason why it happens. It appears that mastodon.social and concert.io are depending upon fastly.net for CDN services and hence there is an overlap of IP address which #TrackerControl identifies as an outgoing request to the Advertising portal concert.io.
Apologies for the trouble @Gargron. I will take this as an issue with #TrackerControl to see what can be done.