See Dick Continue to Run (2) - S2-E1
Other mistake: When Dennis Rodman sees Harry, Tommy, and Sally at the hardware store, he addresses all three by name and asks what they are doing on Earth. If he didn't previously know they were on Earth, then he couldn't have known they were going by those names, as they chose those names after arriving at Earth. Harry even mentioned in a later episode that the names Tommy, Dick, and Harry were chosen by chance when they saw the phrase "Every Tom, Dick, and Harry" written down.
Dick's Ark - S6-E12
Character mistake: Sally tells Dick that he's jealous of her gig as a weather girl because he's never been on TV. However, Dick did appear on TV as a panellist on a talk show highlighting Dr. Strudwick's physics book in the season 4 episode Dick vs. Strudwick. Dick ended up turning the show into a Jerry Springer-like fiasco, and Sally even attended the taping. (00:10:40)
Continuity mistake: As Harry is leaving the party he is dry despite having just been in the shower fully clothed.
Dick Soup for the Soul - S6-E16
Audio problem: When Tommy is talking about how he recruited Sally to help him get into the fraternity, but has gone mad with power, at one point it switches to a wide shot and you can see his mouth isn't moving. (00:19:28)
Tricky Dick - S3-E3
Audio problem: In the epilogue when Harry is singing for the garage band, before he takes the guitar and smashes it, you can see the guitar player is strumming, but only the bass guitar and drum parts are audible. (00:21:20)
Proud Dick - S2-E13
Other mistake: When Dick and Sally are playing with the cat toy in the kitchen, they make a lot of joyous noise while doing so. When the shot changes, we see Mary coming up the stairs to a completely silent home, and she can't seem to locate anyone until Harry pulls her into the closet. The kitchen is only a few feet away from the stairway, so not only should Dick and Sally's voices have still been very audible, but at the very least, Sally should have been in Mary's direct line of sight. (00:15:53 - 00:16:20)
Proud Dick - S2-E13
Revealing mistake: When Harry lands in the yard, you can tell he lands on a crash mat, as the grass beneath him shuffles. (00:01:15)
Scaredy Dick - S3-E5
Continuity mistake: Before the offscreen trick-or-treater starts throwing eggs into Mary's house, you can see she already has egg stains on her jacket from previous takes. (00:17:40)
Continuity mistake: When Caryn is on the desk, her back is to the class. After the pledge, when Dick says "never mind" and the camera angle changes, she's now facing the class.
Dick Puts the Id in Cupid - S5-E11
Factual error: At the police station, in lock up, there's a paper on the bulletin board with a phone number "1-800-VICTIM" An 800 number should have 7 letters/numbers instead of just 6.