Lately, I was thinking about it and it can be a good thread. I am sure how you have seen more of these errors.
I go to start writting one which I find today. I was reading the section from a planet named Had Abaddon. You can see it in the Legacy comics.
The error is this. There is a behind the scenes section and it shows the image from Ralph McQuarrie with the mini death stars.
Early concept art for Had Abbadon with two orbiting Death Stars by Ralph McQuarrie.
First, it names them as Death Star and they were painted as a concept from mini Death stars. Second, the planet in background is Coruscant. Never was Had Abaddon. This info is in the SW guides showing the work from Ralph McQuarrie. All the info about the relation between Had Abaddon and this paint was invented.
Thinking about Ralph McQuarrie, it looks as if Disney had not bought the work from all the Star Wars stuff (comics, books, guides and more), it looks as if Disney had bought only the stuff from films because clearly they are adding the stuff from Ralph McQuarrie made for the films in their new films.
By example at Rogue One, the castle from Darth Vader at Mustafar, it looks as some painted before from Ralph McQuarrie. Many things are similar to his paints.