It is highly usual to have 2 children with the same name, unless the first child had died. Note that the first Isabella, born 1792 died 1817. The second Isabel was born 1808. This information came from the Ancestral Files at LDS. I have put this in our family record, however, I do not believe it to be correct!
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MyHeritage family tree
Family site: M(a)cKenzie - Kunkel Website
Family tree: 330383-1