@[deleted]0It's because your regex is more than it needs to be. The system is going to take the Topic ID and try to match it to the regex, not the entire URL. Your regex is saying:/ -> begin regex.* -> match anything before, any amount of times(18|20|21|22) -> match "18", "20", "21", or "22".* -> match anything after, any amount of times/ -> end regexiu -> options for "i - case insensitive" and "u - unicode"... when it only needs to be:/ -> begin regex(18|20|21|22) -> match "18", "20", "21", or "22"/ -> end regexI just tested the above and confirmed it works.I hope this helps! Cheers.