I really wish I still had the link, but there used to be a website that listed a bunch of times in which machine learning was used (mostly via reinforcement learning) to teach a computer how to play a video game and it ended up using perverse strategies that no human would do. Like exploiting weird glitches (https://www.youtube.com/watch?v=meE5aaRJ0Zs shows this with Q*bert)
Closest I've found to the old list I used to go to is this: https://heystacks.com/doc/186/specification-gaming-examples-...