These requests to dead S3 buckets *must* have been causing a lot of scheduled tasks to fail, and no one was looking into it because "that's not used any more, we'll clean it up later".
Except some of them could have been exploited for full compromise:

8 Million Requests Later, We Made The SolarWinds Supply Chain Attack Look Amateur
Surprise surprise, we've done it again. We've demonstrated an ability to compromise significantly sensitive networks, including governments, militaries, space agencies, cyber security companies, supply chains, software development systems and environments, and more. “Ugh, won’t they just stick to creating poor-quality memes?” we hear you moan. Maybe we should, maybe


