1) How can I tell you my account without putting my email address here?

2) I use both

I am really confused now... I have syncing disabled yet overnight my bookmarks increased from 1291 to 2582 both online and in my browser, how can that be???

Also note that the backups are enabled but the timing of them is completely erratic and

  I restored 

Yet the number of bookmarks doesn't match...this is just so unstable I have no idea whats going on but this has turned into a daily project just to cleanup the mess every day. I will disable the extension until something changes!!!

Wow this is such a major issue and I will help in anyway I can but I cleaned up everything again today in FF and left the Chrome offline and disabled, to isolated just what would happen with FF. I then turned on the sync and backup again and in less than 3 hrs my bookmarks increased from 1291 to 7746!!!!

browser

What do you mean??? If I no longer wanted a link I deleted it. If a link should have been in a different folder then I moved it. All manual decisions

1) YES

2) YES

I had both browsers open for about 2 hrs with syncing and backup enabled on both. I was working in FF cleaning up links and folders when all of a sudden the sync happened and I could actually see my toolbar reorganize and the duplicates create. I immediately turned off syncing and then later turned off the backups.

The top image shows Chrome and it didn't even bother creating any backups.

The bottom image is FF and shows the duplication.