Starting a title with a number is a bad idea as you describe. The problem is that the slug is ignored by Discourse and that if you start a slug with a number and that number matches a topic_id you’ll get that topic.
These both resolve to this topic
https://meta.discourse.org/t/112491
https://meta.discourse.org/t/112491-degggrdff
You’ll need to change your convention to use titles like 'region 5454 section 3" rather than 5454-region-3
Oh, but if the final topic id is there, then the right thing happens. Why are you removing the topic_id?
https://meta.discourse.org/t/1234-topicslug-with-numbers-gets-translated-into-topic-id/112491/3