Continuity mistake: Harris was born in 1997 (in season 9) so in 2018, that makes her 21 years old, but in the 2018 revival and its spinoff "The Conners", she is depicted as 17-18 years old and attending high school.
Canoga Time - S1-E11
Audio problem: When Dan and Roseanne start throwing things in the yard, you can hear it's not hitting grass or a porch, it's hitting a floor (from the set it was filmed on).
Continuity mistake: In the episode Terms of Estrangement Part 1, Roseanne goes for an interview at "The old Wellman Factory" which was closed down and turning into a printing press. Then, in the episode Lanford's Elite, Roseanne and Jackie team up with Edgar Wellman Jr. to try to save the factory from shutting down by paying off past due debts and making all the current employees part owners.
Altar Egos - S6-E25
Continuity mistake: When Roseanne and Dan are at the kitchen sink discussing whether Jackie is or isn't in love with him, Dan's robe blatantly switches from open to closed.
Audio problem: During the phone conversation with Darlene and David, you can hear the audience laughing following a line from David. The scene then cuts to Darlene's end for a moment. When we cut back to David, we hear the end of the previous laughter.
Rear Window - S7-E13
Visible crew/equipment: After Dan grabs the beer during commercial break, a boom mic swings in at the top of the screen for a moment. (00:03:05)
Visible crew/equipment: During the final scene, a boom mic is at the top of the screen in the first shot for 1 second.
Visible crew/equipment: In the final scene, at the start of "Lunch Box Girls", a boom mic is seen at the top of the screen for 1-2 seconds.
Audio problem: When Becky runs down the stairs and yells "Mom!" you can hear the echo throughout the sound stage.
Continuity mistake: When Dan heads back to the bar after hitting the drywall with his hammer, Roseanne goes there to find him. While they're talking, we see a crooked painting to Dan's left, and a lamp hanging straight. Then, in the next shot, suddenly the painting has been straightened, and the lamp is crooked. (00:17:55)
Scenes from a Barbecue - S3-E24
Continuity mistake: Becky went from having long hair throughout this season to having very short hair in the last episode (ep. 23), then back to long hair in this episode (ep. 24).
Suggested correction: I'm not sure what the ruling on these types of mistakes is, but "Dances with Darlene" (ep23 and production code 425) was aired out of order. It was the last episode filmed in the season and meant to be a season finale, but aired prior to "Scenes from a Barbecue" (production code 423). One reason seems to be this is a Mother's Day episode and aired on the Tuesday before Mother's Day, and the next episode was Jay Sanders' last appearance.
Halloween IV - S5-E7
Plot hole: Just before Roseanne arrives at the Lodge Halloween party, Fischer is holding a small object in his hand that he slightly adjusts to a certain position. Roseanne then arrives dressed as Lady Liberty. When she raises her torch and asks someone for a light, Fischer immediately flicks on the cigarette lighter that he was already conveniently holding and ready to ignite for no apparent reason.
Plot hole: Before her date, Becky asks Roseanne to help style her hair. After the family teases her, Becky says she'll just do it herself. Shortly after, she comes downstairs with a perfectly executed and complicated French-braid hairstyle that would be all but impossible to have done by herself and in such a short amount of time.
