Up to now, I think new bookmarks are added at the end of the list, unless you move them to a folder. What is different on yours? Or how did you sort them in a different way?

Sorry, my question was poorly worded. I know new bookmarks are added at the end of the list, and I sort them alphabeticaly in ascending order on my PC. But, up to now, when the SYNC function of firefox was executed on my PC (manually or automatically), the bookmarks were sorted on my smartphone Android too. My smartphone is connected to my PC Firefox. Similarly, any modification made on my PC was reflected on my smartphone. I think it's since the last update of firefox that the SYNC function doesn't work anymore.