There have been a number of failures of this test on the master branch
https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+bwc-tests/1262/console
https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+intake/2339/console
https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+default-distro-bwc-tests/180/console
In all cases the error is
java.lang.AssertionError: Failure at [indices.stats/10_index:50]: field [indices.test1.uuid] doesn't have a true value
Expected: not null
but: was null
The failure reproduces if you massage the reproduce line a little by changing :qa:mixed-cluster:v6.4.0-SNAPSHOT#mixedClusterTestRunner to :qa:mixed-cluster:v6.4.0-SNAPSHOT#bwcTest
./gradlew :qa:mixed-cluster:v6.4.0-SNAPSHOT#bwcTest -Dtests.seed=C06428A7AE0846BD -Dtests.class=org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT -Dtests.method="test {p0=indices.stats/10_index/Index - all}" -Dtests.security.manager=true -Dtests.locale=he-IL -Dtests.timezone=NZ
The test has been muted in b655c11
#31871 looks the likely cause
There have been a number of failures of this test on the master branch
https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+bwc-tests/1262/console
https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+intake/2339/console
https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+default-distro-bwc-tests/180/console
In all cases the error is
The failure reproduces if you massage the reproduce line a little by changing
:qa:mixed-cluster:v6.4.0-SNAPSHOT#mixedClusterTestRunnerto:qa:mixed-cluster:v6.4.0-SNAPSHOT#bwcTestThe test has been muted in b655c11
#31871 looks the likely cause