It looks like the transcription on Ancestry is incorrect. The image of the family history book says “child of Charles Blackwood-Lois Barrett” but the transcription says the father’s name is Charles Barrett.
So Sourcer will use what is in the Ancestry transcription.
You can submit a user correction on Ancestry.
To edit the citation just go into edit mode on the WikiTree profile and change two places:
1 before the <ref> change “Clarence, son of Charles Barrett, married Alla Eugenia Tharp on 10 April 1913.” to “Clarence, son of Charles Blackwood and Lois Barrett, married Alla Eugenia Tharp on 10 April 1913.”
2 Within the ref change “Clarence Edmond, son of Charles Barrett, marriage” to “Clarence Edmond, son of Charles Blackwood and Lois Barrett, marriage”