Collection Pre-Request script can't be changed or deleted

I created a collection and added a Pre-Request script at the collection level. When I learned that this Pre-Request script was run before every request in the collection, I removed the script and saved the collection. However, that script won’t go away. It still runs even though it’s not there anymore. I wrote a different Collection level Pre-Request script and saved it. It doesn’t have any effect. The original Pre-Request script still is what executes. I tried restarting the Postman application, but that had no effect. No matter how I try to alter the Collection level Pre-Request script, the original version is what gets executed. Am I don’t something wrong, or is this a defect in Postman?