PowerCMS Template pages - non-existent pages default to show most recent ID
I have a PowerCMS template page set up to display surveys in a repeating list. The URL for a typical survey would be, for example:
However, if someone tries to access a non-existent survey (for example one that's been deleted from the site), instead of getting a page not found error it's defaulting to show the most recent survey instead. In fact, you can add any words you like after ?ID= and it will still show the most recent survey. I've never seen this before - how can I prevent it from happening?