Our most recent master BWC test run failed against versions 7.0.x and 7.1.x with the same test failures indicating we either made a BWC incompatible change in master or perhaps just the test needs updating.

The build run in question included this commit, which might potentially be related. @original-brownbear any thoughts?

Example build scan: https://gradle-enterprise.elastic.co/s/dpoop7fvn2rwq/tests/failed
Jenkins build with links to each BWC version: https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+bwc/471/