Queasy Rider - S2-E1
Continuity mistake: As Doug is telling Carrie he hates the bike, his beer and crisps vanish instantly from the sofa. (00:19:20)
Continuity mistake: At the start, the amount of coffee in the pot changes instantly. (00:02:25)
Window Pain - S5-E2
Continuity mistake: When Doug and Carrie are arguing outside the neighbour's house, Doug takes a big swig from the Scotch bottle and then puts it on the ground. After the police pull up, the shot cuts back to Doug and Carrie. Doug picks up the bottle from the neighbour's porch railing. (00:42:45)
Continuity mistake: In the middle of the night when Carrie finds Doug rolling the ham-n-swiss doobie in the kitchen, he dips it in the mayo, and when the shot changes, there's no mayo on it and he dips it again, then takes a bite. (01:25:00)
Continuity mistake: When Doug is talking to Carrie in the kitchen about his ideas for the sandwich shop, lights reflecting in the living room windows behind Doug turn off and then back on when the shot changes between Doug and Carrie. (00:11:00 - 00:11:35)
Continuity mistake: When Doug jumps out of the porta-potty before the rival ice-cream truck smashes through it, the door is open and Doug immediately lands on the ground; but when the shot changes, the porta-potty door is closed and we can't see Doug rolling onto the ground. Also, when the truck smashes into the porta-potty, liquid splashes everywhere; but when we see Doug in the next shot he is dry and no liquid on the ground around him. (00:12:55)
Continuity mistake: When Doug and Carrie are in Deacon's kids' room, Carrie is changing the baby and between shots the baby changes from lying down to sitting up. (00:15:00)
Inner Tube - S3-E17
Continuity mistake: At the start at IPS, Doug's tie is looped over itself twice. Camera cuts and now it's not looped at all. (00:02:30)
Continuity mistake: When Doug and Deacon are at Cooper's at the start, Doug's straw changes position between shots. (00:02:00)
Continuity mistake: Deacon says "How do we know cutie-pie isn't cutie-guy?" then crosses his arms. In the next shot his arms are immediately uncrossed and on his hips when Doug replies. (00:06:00)
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.