As noted in her profile notes, Zilpha was married to Samuel Jeffcoat I, not William. Aside from her profile notes, these sites list her husband as Samuel:
https://www.findagrave.com/memorial/165904254/rachael-jeffcoat
https://www.andalusiastarnews.com/2015/02/07/jeffcoat-family-of-eng...
https://ancestors.familysearch.org/en/LK9P-FXZ/rachael-bolin-1745-1791
