Thanks for sharing as this is good info to have. It's nice to be able to see the hairline crack in that other one so people know what to look for since it's clearly getting ready to fail too.
I don't have this set up so I'm not familiar with it, but what is that second hole for anyway? I can see the other hole is to put the pin in, but does the hole where it broke get used for? As you can see in your photo, by the time they cut that hole and the slot down the middle, it doesn't leave a lot of metal left for support. But the same is true of the bigger hole that the pin goes through.