This must be a regression bug in AWS's internal system. At a past job (2020) we used S3 to store a large amount of genomic data, and a web application read range requests to visualize tiny segments of the genetic sequence in relevant genes - like 5kb out of 50GB. If AWS had billed the cost of an entire genome/exome every time we did that, we would have noticed. I monitored costs pretty closely, S3 was never a problem compared to EC2.

It also seemed like the root cause was an interrupted range request (although I wasn't fully clear on that). Even so that seems like a recent regression. It took me ages to get that stupid app working, I interrupted a lot of range requests :)