Corrected entry: In the episode where Mark gets drunk and punches the jukebox at The Lobo while Dan is playing poker with his friends Roseanne is out with the girls, supposedly at The Lobo. Roseanne is never shown there and Dan even asks at one point how many beers she had. Roseanne has no knowledge of Mark's accident even though both characters were supposed to be there at the same time.
Corrected entry: This is actually from the last few episodes of season 5, with the plotline of Darlene being accepted to an art school in Chicago, and David not. Problem: they both applied to the same school, and at least Darlene was applying into the writing program (I don't remember if David was, too) and there is only one art college in Chicago that has writing programs: Columbia College. And it wouldn't have been possible for David to have been rejected from there - Columbia has open admissions.
Corrected entry: In the episode Maybe Baby, Roseanne has an amnio and they think something is wrong with the baby so they have a second one which turns out fine. The doctor reveals that it's a girl but then later, she has a baby boy, Jerry. The only way he could have been wrong would be if maternal cells were tested instead of fetal cells.