NFTs are commonly sold via auction on marketplaces like OpenSea and Rarible, and even traditional auctioneers like Sotheby’s and Christies now hold auctions for NFTs. Bots are commonplace at online auctions, typically sniper bots that place a winning bid at the last possible moment of the auction to maximize the chances of winning an item at the cheapest price. However, bots are also being used to manipulate NFT auctions in another way.
Spinner bots add an item to their shopping cart simply to make that piece of stock unavailable to other customers. This creates denial of inventory, preventing customers from buying the item from that site and forcing them to look to the secondary market instead.
https://www.netacea.com/blog/how-bots-skew-nft-prices-for-big-profit/