Daria (1997)

Fat Like Me - S5-E3

Factual error: When we see Tiffani and Stacy talk on the phone with Quinn (on the other end), we hear a call waiting beep from Quinn's end (but the camera still on the two girls' side) and Quinn mentions she's getting a call from Sandi. The mistake is only Quinn herself would have heard the "beep" and the other girls would have just heard Quinn's voice cut off with dead air for a second. Tiffani and Stacy should not have heard that "beep" like it was shown in the episode.

Life in the Past Lane - S5-E9

Factual error: When people are dancing around the car that Daria and Tom are sitting in, the crescent moon is shown in the night sky in the background over the horizon, with the crescent facing upwards away from the horizon. This would be impossible as the crescent can only face down into the horizon at night (never away from it).