Hello
Well first of all I want to give you a greeting and then I come to show you a bug I just found.

Well the error is the following, I wanted to proclaim the minecraft verdict 17w15a and wanted to test it in a custom world and it turns out that when I give the custom button crash the minecraft I leave a video for you to watch.
Https://www.youtube.com/watch?v=X1Y-wduI84w&feature=youtu.be

I hope they can solve it.

regards

PS: sorry for my English, I had to use google translator xD