Travis builds: https://travis-ci.org/aaronjorbin/develop.wordpress
Travis config: https://core.trac.wordpress.org/browser/trunk/.travis.yml
notifications:
45 slack:
46 rooms:
47 secure: WuMCpfgrm0GIdPbYzsGOsakZ5x7QIbEBwD+CPHVXGKbL3ZbqQ+BVcDRnMiwzxjgf1vzg2de0taXCSMGKBxsWce23NZkOnmwPdIB8XOnwDV7T7zylgYD5S7p3gI6gV0l8Y3/gROdXFZap6viC1qRr4E79ow53RKk7E3WyOo7TWqo=
48 on_start: never
49 on_failure: always
50 on_success: change
The below shows multiple notifications for builds 4615 and 4616, there should only be one notification for each, not contained in the screenshot is the same scenario for builds 4607, 4608, 4609, 4610, 4611, 4612, 4613, and 4614.

The above is also happening for the BuddyPress tests here https://travis-ci.org/buddypress/BuddyPress/builds as such the issue is not isolated to a single Travis CI repo.
Travis builds: https://travis-ci.org/aaronjorbin/develop.wordpress
Travis config: https://core.trac.wordpress.org/browser/trunk/.travis.yml
The below shows multiple notifications for builds 4615 and 4616, there should only be one notification for each, not contained in the screenshot is the same scenario for builds 4607, 4608, 4609, 4610, 4611, 4612, 4613, and 4614.

The above is also happening for the BuddyPress tests here https://travis-ci.org/buddypress/BuddyPress/builds as such the issue is not isolated to a single Travis CI repo.