When Autosync/Autobackup is on, it refreshes "the bookmarks" by deleting one by one, then replaces step by step on the FF bookmarks tab (I see what's goin' on), as well as most of my bookmarks in FF were deleted. Fortunately, I was able to restore them back.
This is an issue for 2 months, I think.
It says my quota is full.
Definitely, I lost my trust!