Thanks for reporting this. The issue is that folder-level classifiers store the full folder path internally (like “YouTube (no shorts)”), but when you move that folder into a new parent, the path changes to “YouTube - YouTube (no shorts)” and the classifier can’t find it anymore. So it looks like it’s still there in the trainer, but it stops matching stories after a refresh.
I’ve pushed a fix that updates all folder-scoped classifiers (tags, titles, authors, etc.) whenever a folder is moved or renamed. Your existing classifier should start working again once this is deployed. In the meantime, you can work around it by opening the trainer on that folder and re-saving the disliked tag.