This always happens when Amazon has one of their conferences with lots of product announcements. Whether Amazon employees are actually making submissions here, or whether it's all purely organic, I can't say. But it's pretty much par for the course, at least over the last couple of years.

Their annual conference is happening right now, where they are announcing new products.

https://reinvent.awsevents.com/

It's just because Amazon's ReInvent conference is happening right now, so there are plenty of product announcements happening that are relevant to the HN community.

The same thing often happens when Google, Apple, Microsoft, etc. are running their big developer conferences.