diff --git a/taskcluster/ci/test/test-platforms.yml b/taskcluster/ci/test/test-platforms.yml
index eeb22a9dc6f38..94c8a0ba6e1f0 100644
--- a/taskcluster/ci/test/test-platforms.yml
+++ b/taskcluster/ci/test/test-platforms.yml
@@ -19,7 +19,7 @@
 ##
 # Linux platforms (matching /linux.*/)
 
-linux32-shippable/opt:
+linux1804-32-shippable/opt:
     build-platform: linux-shippable/opt
     test-sets:
         - linux32-tests
diff --git a/taskcluster/taskgraph/transforms/tests.py b/taskcluster/taskgraph/transforms/tests.py
index 1d1d48cf3dbfe..bc4d607f24e4b 100644
--- a/taskcluster/taskgraph/transforms/tests.py
+++ b/taskcluster/taskgraph/transforms/tests.py
@@ -571,7 +571,10 @@ def set_defaults(config, tests):
         test.setdefault('loopback-audio', False)
         test.setdefault('loopback-video', False)
         test.setdefault('limit-platforms', [])
-        if config.params['try_task_config'].get('ubuntu-bionic'):
+        # Bug 1602863 - temporarily in place while ubuntu1604 and ubuntu1804
+        # both exist in the CI.
+        if ('linux1804' in test['test-platform'] or
+                config.params['try_task_config'].get('ubuntu-bionic')):
             test.setdefault('docker-image', {'in-tree': 'ubuntu1804-test'})
         else:
             test.setdefault('docker-image', {'in-tree': 'desktop1604-test'})