When Data and Okona get off the Turbolift, it shows they are on Deck 10. However, when Okona approaches Lt. Robinson's quarters, it shows they are on Deck 8.
When Worf gets off the turbolift on Deck 10 to collect Okona, the doors of quarters of the female crewmember read Deck 7. When Worf and Okona enter the turbolift, the doors read Deck 11.
When Capt. Okona asks where "806" is (Lt. Robinson's quarters), Data points out a nearby door. But after Okona enters, the door closes and the room number "08 0669" is shown.
When the computer is listing comics for Data, he says "that one" and the computer starts clearing the other names before Data can identify the one that he meant.
In the conference room during the discussion of Okona's fate, we see a round wall decoration behind Captain Picard and Counselor Troi. When Okona leads Yannar to the opposite side of the room to discuss her decision, we see the same decoration on the wall behind them. Later in the same scene, the decoration re-appears behind Picard and Troi.
After Okona beams aboard, he leans against the transporter console equipment and it wobbles.
We hear Okona call Riker 'Commander', but his mouth is saying 'Captain'.
It's well established that the Holodeck exit only appears when explicitly requested. However, when Data and Guinan exit at the end, the exit sound effect occurs without either character requesting it.
Data is summarizing the Comic's joke about Tip O'Neill and the briefcase that looks like a fish by stating, "So the juxtaposition of gender and an amphibian briefcase..." Data should know the difference between fish and amphibians.
Okona asks if he heard a woman's voice and talks lecherously about women, but says nothing about Troi even though she is plainly visible on the bridge.
Upon Worf's recommendation, Picard orders that Okuna only have limited access to the ship. Data then leaves him to walk freely about the ship without an escort and into multiple crew quarters.
At the end, when Data is feeling low following his attempt at stand-up comedy, Guinan misquotes William Shakespeare saying "being able to laugh is not the end-all and be-all of being human." The correct saying is "be-all and end-all."