alt Hacker NewsCoding use cases? This is penetration testing behavior. It was discovering what its capabilities were by discovering an API endpoint, trying it and seeing what happens. It was not discovering what its capabilities were intended to be, say by looking at the forms and documentation on the website. If this were coding behavior you would end up with crap code, bypassing interfaces and using private access paths just because it can.
Sure, it's pen testing behaviour. It's also debugging behaviour which is a core part of coding. In my experience, I have found myself at times dealing with and interacting with external systems that are not my own, where I don't have the source, or are under-documented, or are behaving contrary to the documentation. I'm unsurprised this is a core thing they're training these models for, because it's something I find way more valuable than their below average coding ability.