Apparently when ordering server racks from Amazon, they occasionally accidentally ship too many, but they are so expensive to ship back, they have you keep them. This person ordered 1 42U rack, got 9:

https://old.reddit.com/r/homelab/comments/unbqtg/moving_to_a...

Here's another person who ordered 1 12U rack, got 12 12U racks:

https://old.reddit.com/r/homelab/comments/giaw1x/i_bought_1_...

Same:

https://old.reddit.com/r/homelab/comments/eemzef/so_amazon_s...