No, not necessarily a problem in either of those things. As I said, it ruptured way below the pressure the tank was rated for - nothing wrong with the design there. And I don't know if it's been explicitly confirmed or not, but those tanks get tested above that pressure before they get installed. The ship had already done a single-engine test firing so it must have actually been pressured up to that already when it did that previously.
It sounds to me like something happened that damaged the tank after it was already in place. That would be my guess. Something banged into it and nobody noticed.
I'm interested to see how this turns out. My prediction is that the AI trained from the results will be insane, in the unable-to-reason-effectively sense, because we don't yet have AIs capable of rewriting all that knowledge and keeping it consistent. Each little bit of it considered in isolation will fit the criteria that Musk provides, but taken as a whole it'll be a giant mess of contradictions.
Sure, the existing corpus of knowledge doesn't all say the same thing either, but the contradictions in it can be identified with deeper consistent patterns. An AI trained off of Reddit will learn drastically different outlooks and information from /r/conservative comments than it would from /r/news comments, but the fact that those are two identifiable communities means that it'd see a higher order consistency to this. If anything that'll help it understand that there are different views in the world.