Game crash when going near structures

Game crashes going near certain structures if there is a custom advancement that detects it. Only tested with desert pyramids. Multiple crash reports in attachments.

To Reproduce:

1. make new world in 18w11a
2. create a datapack that has an advancement that is granted by going in a desert pyramid. My example in attachments
3. put it in the new world
4. use /reload
5. find desert pyramid
6. game crashes