No Retreat - S4-E5
Continuity mistake: When Horseback riding Doug is holding on to the straps with either one or two hands depending on the shot. (00:16:50)
No Retreat - S4-E5
Continuity mistake: When horseback riding, the track behind them is constantly changing. For example, when Doug hits the tree, the tree then vanishes. (00:17:40)
No Retreat - S4-E5
Continuity mistake: When Doug tells Carrie at the start he is telling his jet ski story, the tongs he's holding swap hands instantly. (00:00:45)
No Retreat - S4-E5
Continuity mistake: During the opening scene in the backyard, Deacon finishes his beer and puts it down. In the next shot of Deacon he is holding the beer again. (00:00:10)
No Retreat - S4-E5
Other mistake: In the opening scene when Doug is cooking hotdogs for his friends, the smoke coming from the BBQ is very fake. (00:00:20)
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.