I finally got hold of 'The Dukes' cartoon series on DVD and I didn't think it should be excluded from this thread. I appreciate that cartoons have different rules to live-action so I've let some things slide, but these I couldn't.
First are the seats/seatbelts in The General. About half of the time no one is wearing a seatbelt, as shown in the first picture. In the second picture the front seat occupants have conventional over-the-shoulder seatbelts, although the belts disappear behind their backs - not much use in an accident!. In the third picture Vance's seatbelt is across his left shoulder. The fourth picture shows all three occupants wearing seatbelts although the front seats have mysteriously disappeared. By the fifth picture it's only those in the front with belts again, but the belts are now attached to the roof. Finally the last picture shows the top of seatbelts attched to the top of the A-pillars by the windshield. I guess they added the belts because of the target audience (in the live-action show The General hardly ever seems to have seatbelts), but they could've at least been consistent.
Both the pictures below show views in rear-view mirrors. In the one on the left they forgot to reverse the image.
During a river crossing (I think from 'The Dukes in Urbekistan') we get a close-up of The General's rear. The license plate clearly shows "CHN 920" instead of "CNH 320". It's correct in other shots that I've checked. Incidentally, with all the countries in the world to choose from, why did they have to make up Urbekistan?. Were they worried that the people of Uzbekistan would take offence?. Likewise, in 'The Dukes in Switzerland' the secret police are from Slavonia which sounds suspiciously like the European country Slovenia (although it was still part of Yugoslavia when the cartoon was made). If anything, the secret police sound more like the Stasi that operated in East Germany until reunification in 1990.
The final one here may not be a blooper, but I bet no one at Hanna-Barbera considered it. In 'Dukes in Scotland' the story revolves around a money counterfeiting operation, but they are counterfeiting Bank of England (English/Welsh) bank notes. Scotland has it's own bank notes that are issued by retail banks, not central banks and don't have the Queen's head on them. I accept that they could've been making English/Welsh notes because they are easier to dispose of (Scottish notes can be refused in England and Wales and are not accepted by banks and exchange bureaus outside of the United Kingdom). I also wonder why they would bother counterfeiting the lowest denomination note. Most forgers go for £20 notes. The £50 note had entered circulation in 1981, but even today they are scrutinized a lot more than other notes due to their higher value.