Safari bookmarks appear twice after being moved to a folder
I am having a problem with the bookmarks in Safari. I have created bookmark folders for broad categories, and within each category there are other bookmark folders (sub folders?). When I "add a bookmark" for a website, it appears at the bottom of the list of bookmarks, then I drag it to the appropriate folder. However, sometimes, maybe often, the website is bookmarked in the folder, but is still listed outside the folder. So, the bookmark is listed twice. This redundancy makes for a very long list of bookmarks. When I drag a bookmark to a folder, shouldn't that be the only place for it? I am using a Mac with Sequoia 15.7.7
iMac 21.5″, macOS 15.7