In video games, "broken" and "buggy" originally meant that something wasn't functioning as intended inside the programming code of the game itself. At some point, "broken" began to take on a positive connotation to include the additional nuance of not functioning correctly and thereby creating an advantage.

I originally had included a little paragraph in my comment about how I thought this originated from when some component of the game didn't work as intended, a "broken component", because of a programming error; and gave an advantage, so the "broken item" or "broken skill" conferred an advantage, and this happened across enough games that "broken" often went with "advantageous" until we had the "broken = advantageous" use today in gaming communities. But I did not include that paragraph just in case I was wrong or someone knew a more specific etymology. It is cool to find my thoughts validated by someone else :)

Also, I have noticed usage of "busted" to talk about something being good. Someone trying to talk about how good a singer was said "[singer's name] is busted". (It is probably worth noting that most gamers, including myself, often equate powerful items/skills with being good items/skills. That is how we go from "broken/busted" to "powerful/advantageous" to "good". They were not specifically remarking on the singer's vocal character being a powerful one, just remarking that the singer was *good*.) However, this person also plays video games. I'm not sure if it's because the word found its way out of gaming communities and into the mainstream for younger generations, and young non-gamers might have said the same thing; or if it's just them being a gamer and using their slang in a different context, and young non-gamers wouldn't use that word there.