I'm not completely sure if this is a bug or not, but the wiki says it should be no more than 40k for one item so I wanted to list it here. I took a brief video of the price and a screenshot of what it ended up being (an item worth 20k).

That doesn't look like a mistake to me based on the official price of the item. The mystery box works based off of the official price. Unfortunately for the higher official priced items it is usually a miss.

Yeah I thought it might be something fun but it was not. XD As long as it's not a bug though, that's mainly what I was concerned about.