I have no idea where the duplication came from...a couple of days ago...there were only the ancestor couple with their correct ancestor branches. When I looked this morning...the husband had been duplicated as a 'side loop' connected to the same wife. I 'edited' the duplicate husband, clicked on 'delete this person'. And Ancestry deleted both the duplicate, the original, his wife and all of their ancestor branches.
"Undo" would not undo the deletions!
What bothered me more was that Ancestry.com then proceeded to totally delete the same branches of ancestors in FTM when they went into sync. And there was no way to protect FTM.
I had to reload a previous backup to bring the deleted branches back into existence.
Your other comments to me state that newer revisions ALWAYS take precedence. So I am hoping that my restoring the deleted branches on FTM will also restore them in Ancestry.