Random grass block?

We were playing survival in the latest snapshots with one of my friends, and my friend got a grass block in his chest. We did not have silk touch, and we did not have cheats enabled (for sure!). We both did not know, how that happened. I don't know how this happened, but it happened. It did not happen with us by the way before. I tryed that there is maybe a glitch when you break grass with shears, but no. Not shears. Any ideas why this happened?