diff --git a/.buildkite/scripts/common/env.sh b/.buildkite/scripts/common/env.sh
index 89121581c75d..ac80a66d33fa 100755
--- a/.buildkite/scripts/common/env.sh
+++ b/.buildkite/scripts/common/env.sh
@@ -56,8 +56,8 @@ else
 fi
 
 # These are for backwards-compatibility
-export GIT_COMMIT="$BUILDKITE_COMMIT"
-export GIT_BRANCH="$BUILDKITE_BRANCH"
+export GIT_COMMIT="${BUILDKITE_COMMIT:-}"
+export GIT_BRANCH="${BUILDKITE_BRANCH:-}"
 
 export FLEET_PACKAGE_REGISTRY_PORT=6104
 export TEST_CORS_SERVER_PORT=6105
diff --git a/.buildkite/scripts/packer_cache.sh b/.buildkite/scripts/packer_cache.sh
index 45d3dc439ff4..617ea79c827b 100755
--- a/.buildkite/scripts/packer_cache.sh
+++ b/.buildkite/scripts/packer_cache.sh
@@ -2,6 +2,7 @@
 
 set -euo pipefail
 
+source .buildkite/scripts/common/util.sh
 source .buildkite/scripts/common/env.sh
 source .buildkite/scripts/common/setup_node.sh