Pier, my concern would be deleting the bookmarks from the other 3 devices and then when you turn on sync again it deletes the bookmarks on the 4th device. How about trying this: Turn off syncing and then fix the bookmarks on one device and then turn on syncing again. Have you tried this? Let me know if that worked. I keep having to delete duplicate notes (mail & notes item on icloud sync)
Actually, this may be of interest.
I deleted all bookmarks on my iPhone and my iPad via turning off bookmarks sync. Then I fixed the bookmarks on my desktop iMac. Then I turned on Bookmarks on iPad and iPhone, and iCloud copied the bookmarks from iMac to the other two devices.
Seems it's something is better than nothing department. I assume, if your preferred Bookmarks were on the iPhone or the iPad, you could erase the others, then restart the sync, and iCloud would sync the Bookmarks on whatever device to the other devices with no Bookmarks.
This worked for me. Thanks!
My problem was on my iPhone 4S with iOS5. I got a photo app that needed to reference FaceBook. When I attempted to log in to FB, nothing worked but it sent me on an endless loop creating multiple Bookmark Menu/Bookmark Bar folders. The next time syncing took place I was adding 3743 bookbarks. Ouch!!
I tried deleting the extra folders in Safari on my Macbook which seemed to work. Then a few minutes later they all came roaring back. My support search found your tip - for which I am truly grateful.
This took me a alot of playing around to get things working correctly. I was having the exact same duplication issues everyone else was having. Here's how I managed to get things working correctly.
1. Turn off bookmark syncing on every single OS X and iOS 5 device you own.
2. Select a "master" computer where you can clean up your bookmarks. Export your current bookmarks to play it safe.
3. Now clean up your bookmarks so they are setup exactly how you want them. While you're doing this make sure you deleted every single "folder" listed in the bookmarks pane on the left side of the browser window. The actual book marks that are displayed are the ones listed under the "collections" line. The blue extras being sync from iCloud.
4. Exported the "clean" bookmarks.
5. Turn on iCloud bookmarks syncing and agree to the merge.
6. Go to every other OS X and iOS device and delete bookmark on all these devices.
7. By now the only thing on iCloud will be the cleaned up bookmarks from the "master" computer. Turn on iCloud bookmarks syncing on one of your devices and wait for the bookmarks to sync.
8. Once you know that the second device has synced correctly (it will if you deleted all the extra stuff as directed) then try your next device and continue with all your remaining devices.
This will work as you expect it to as long as you clean EVERYTHING out of the folder collections from the "master" computer. From this point forward things will sync nicely.
Hope this helps!