The linked source this article was using states: "You might ask, maybe Hertz was charging Lee for having to top the Model 3's battery upon its return? According to the final receipt, the customer gave the Model 3 back to Hertz with the battery 96% full, the exact same state of charge it was picked up with. And, even if Lee hadn't done that, the maximum fee should've been $35"
https://www.thedrive.com/news/hertz-is-charging-tesla-model-...