Elasticsearch version:
5.2
Plugins installed:
[x-pack]

JVM version:
java version "1.8.0_65"
Java(TM) SE Runtime Environment (build 1.8.0_65-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.65-b01, mixed mode)

OS version:
CentOS Linux release 7.2.1511

Description of the problem including expected versus actual behavior:
when trying to predict 2 different aggregation buckets - when the first is null,(not sure why), no prediction is provided for the other one as well.

Steps to reproduce:

this will return prediction for "plt" field:

query1.txt

response:

response1.txt

while this will not return "plt" field prediction:
query2.txt

response:
response2.txt

the only difference in the aggregations order, which should not matter in json documents