Fixer Upper - S1-E12
Continuity mistake: Doug finishes playing the tennis game on the TV with Arthur and goes into the kitchen to get the Cheese Doodles. While talking to Carrie, he puts the Cheese Doodle package on the table with a can of cola behind it. He then goes to get a glass from the cupboard and in the next shot you see the cola is in front of the Cheese Doodles. (00:17:30)
Fixer Upper - S1-E12
Continuity mistake: When Doug is talking to Spencer in the subway, the people in the line behind him change instantly from 2 men to 1 man and 1 woman. (00:19:30)
Fixer Upper - S1-E12
Continuity mistake: At the start, the items in Carrie's hands swap hands instantly. (00:00:10)
Answer: Sara hasn't been mentioned in later episodes, and it suggested in later episodes that she never existed, and that Carrie is an only child. Kevin James stated that the producers couldn't think of an good plots to use with Sara, so they left her out.