Small specialized cases of this have already been happening for nigh-on decades at this point (yes, the internet really is that old).

This article from 2014 describes the process of automated arbitrage in some detail, which was already happening back then:

http://www.dansdata.com/gz146.htm

In summary, some web retailer somewhere runs a bot to buy an item from someone else, mark it up, and resell it. When poorly managed, a bot run by one vendor winds up trying to pull stock from a bot from other vendor doing the same thing, and then that vendor tries to the pull-and-markup scheme on the first vendor. The net result is both bots getting into an infinite circular markup loop trying to buy the same item (which doesn't exist) from each other at an increasingly insane price. This only continues because no living person actually notices.