It seems like people are merging David Barrage Knapp (F-115) with David Knapp (G-905). Numbers from the Nicholas Knapp book.
David Barrage Knapp (F-115) married an Abigail KNAPP and lived very happily and had many children.
David Knapp (G-905) married an Abigail CASE who became Knapp. She died with no issue. Sad story. BUT David Knapp (G-905) married a Sophia KNAPP a couple years later and had a large family. (David and Sophia may or may not be related - and so what if they were distant cousins.)
I don't understand the thought process that any David Knapp married to any Abigail has to be MY David Knapp (G-905). By doing so, the people have him living in two different places and having children concurrently by two different women. (It may be easier to do today with modern transportation but not in 1800.)
Part of doing genealogy is checking for REASONABLE possibilities. And people are turning off their brains believing any Ancestry.com Tree Hint.