iCloud bookmark sync problem...

My bookmark is synced between 2 MacBooks and 2 iPhones (1 of which is used only via wifi)

Recently bookmark is not syncing correctly with no apparent reason.

Symptom:

1. One of the items form the 'favourites bar' - let's call it "Site X" - changes its position to become the first one, ⌘+1

2. "Site X" cannot be deleted or modified anyway.

3. I have tried to delete bookmark.plist from the Library folder and then sync. The result is that only "Site X" remains on the bookmark bar.

4. Only after doing this, you can delete or modify "Site X" - but this dose not sync across devices.

5. Reading List and other items on the bookmark folder cannot be added or deleted. They do not sync either.

6. All the other iCloud products works well. This even includes Handoff of Safari between devices.

I do not mind total deletion of the existing bookmarks but want to recover the ability of the syncing between devices.

Thanks in advance.