Yes, that Joan, Katherine's daughter, married firstly Robert Ferrers, and had two daughters with him, and secondly Ralph Neville.
In fact, as a matter of interest, here's Katherine's children by John:
1. John Beaufort, 1371-1410. He married Margaret Holland, granddaughter of Joan, Princess of Wales. It was their daughter, another Joan, who was Queen of Scots.
2. Henry Beaufort, 1375-1447. Cardinal, I think.
3. Thomas Beaufort, 1377-1426.
4. Joan Beaufort 1379-1440.