Narcissa Johnson, of CT died young - Conflict with two Different Narcissa Johnson/Johnstons

I am asking curator expertise regarding two profiles to sort out. This one and Narcissa A Kinne

Both are listed as daughters of Abner and Lydia but there seemed to be a mix up at some point in time. The Narcissa who died at age 17 is listed on find a grave as a daughter of Abner and Lydia but no mention of the other.

Dates of birth and death in other trees have the dates mixed up between the two Narcissa's

Records at DAR https://services.dar.org/Public/DAR_Research/search_descendants/?ac...

Lists date of death as Aug 1821 not 1816 which many other trees have her death date as 1816 which matches up with the other Narcissa.

Thanks for any help or additional records that can be discovered.