diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/python/BazelPyTestRule.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/python/BazelPyTestRule.java
index a58c8eef1416bc..0ebab840205e60 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/python/BazelPyTestRule.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/python/BazelPyTestRule.java
@@ -57,7 +57,10 @@ public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment env)
             attr("$launcher", LABEL)
                 .cfg(ExecutionTransitionFactory.create())
                 .value(env.getToolsLabel("//tools/launcher:launcher")))
-        .add(attr(":lcov_merger", LABEL).value(BaseRuleClasses.getCoverageOutputGeneratorLabel()))
+        .add(
+            attr(":lcov_merger", LABEL)
+                .cfg(ExecutionTransitionFactory.create())
+                .value(BaseRuleClasses.getCoverageOutputGeneratorLabel()))
         // Add the script as an attribute in order for py_test to output code coverage results for
         // code covered by CC binaries invocations.
         .add(