This is for anyone who may be working with this individual, or who may have a relative path where he shows up incorrectly.
In some paths, he is shown as the father of Annabella Stewart, but he is not. He and Joan Beaufort had three sons. Annabella was the daughter of Joan de Beaufort, but by her first husband, King James I of Scotland. Joan was the widowed (dowager queen) when she married the Black Knight.
Moreover, the Black Knight also shows up in some paths as the father of Edward Neville, 3d Baron Bergevenny. This is an error, of course. The baron's father was Ralph de Neville, 1st Earl Westmoreland.
Thanks for this note Vance. I'm tagging the James Stewart so this discussion will appear on his profile.