diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 2cef7d01..ad99e0b0 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -25,6 +25,20 @@ jobs:
           python-version: "3.x"
           check-latest: true
       - name: Set up chart-testing
+        id: chart-testing-setup
+        uses: helm/chart-testing-action@6ec842c01de15ebb84c8627d2744a0c2f2755c9f #v2.8.0
+        with:
+          version: v3.10.1
+        continue-on-error: true
+      - name: Clean partial chart-testing cache
+        # ct.sh creates the cache dir before verifying the download's
+        # signature, so a failed cosign/Rekor check (transient upstream
+        # flake) leaves a stale empty dir that would make a bare retry
+        # skip reinstalling and fail differently. Clear it before retrying.
+        if: steps.chart-testing-setup.outcome == 'failure'
+        run: rm -rf "${RUNNER_TOOL_CACHE}/ct"
+      - name: Retry chart-testing setup
+        if: steps.chart-testing-setup.outcome == 'failure'
         uses: helm/chart-testing-action@6ec842c01de15ebb84c8627d2744a0c2f2755c9f #v2.8.0
         with:
           version: v3.10.1
diff --git a/charts/mlrun-ce/Chart.yaml b/charts/mlrun-ce/Chart.yaml
index ea023d38..dae90fe1 100644
--- a/charts/mlrun-ce/Chart.yaml
+++ b/charts/mlrun-ce/Chart.yaml
@@ -1,7 +1,7 @@
 apiVersion: v1
 name: mlrun-ce
-version: 0.12.0-rc.3
-appVersion: 1.12.0-rc16
+version: 0.12.0-rc.4
+appVersion: 1.12.0-rc18
 description: MLRun Open Source Stack
 home: https://iguazio.com
 icon: https://www.iguazio.com/wp-content/uploads/2019/10/Iguazio-Logo.png
diff --git a/charts/mlrun-ce/templates/seaweedfs/s3-bucket-init-job.yaml b/charts/mlrun-ce/templates/seaweedfs/s3-bucket-init-job.yaml
index 1ed6b8ca..dead5d10 100644
--- a/charts/mlrun-ce/templates/seaweedfs/s3-bucket-init-job.yaml
+++ b/charts/mlrun-ce/templates/seaweedfs/s3-bucket-init-job.yaml
@@ -44,8 +44,15 @@ spec:
           value: {{ include "mlrun-ce.s3.service.url" . | quote }}
         - name: BUCKET_NAME
           value: {{ include "mlrun-ce.seaweedfs.s3.bucket" . | quote }}
+        # Region is required by the AWS CLI even though SeaweedFS ignores it.
+        # Without it, botocore attempts IMDS region discovery and crashes (CEML-721).
+        - name: AWS_DEFAULT_REGION
+          value: "us-east-1"
+        # Fully disable IMDS lookups as defense-in-depth, independent of region.
+        - name: AWS_EC2_METADATA_DISABLED
+          value: "true"
         command:
         - /bin/sh
         - -c
-        - "aws s3 mb s3://$BUCKET_NAME || aws s3 ls s3://$BUCKET_NAME || exit 1"
+        - "aws s3 mb s3://$BUCKET_NAME 2>&1 || aws s3 ls s3://$BUCKET_NAME 2>&1 || { echo \"ERROR: Failed to create or verify bucket $BUCKET_NAME\"; exit 1; }"
 {{- end }}
diff --git a/charts/mlrun-ce/values.yaml b/charts/mlrun-ce/values.yaml
index c43e2401..265f30be 100644
--- a/charts/mlrun-ce/values.yaml
+++ b/charts/mlrun-ce/values.yaml
@@ -173,14 +173,14 @@ mlrun:
     enabled: false
   api:
     image:
-      tag: 1.12.0-rc16
+      tag: 1.12.0-rc18
     ingress:
       enabled: false
       annotations: {}
     sidecars:
       logCollector:
         image:
-          tag: 1.12.0-rc16
+          tag: 1.12.0-rc18
         enabled: true
     fullnameOverride: mlrun-api
     functionSpecServiceAccountDefault: ~
@@ -231,7 +231,7 @@ mlrun:
 
   ui:
     image:
-      tag: 1.12.0-rc16
+      tag: 1.12.0-rc18
     fullnameOverride: mlrun-ui
     ingress:
       enabled: false
@@ -300,7 +300,7 @@ jupyterNotebook:
     #      - chart-example.local
   image:
     repository: quay.io/mlrun/jupyter
-    tag: 1.12.0-rc16
+    tag: 1.12.0-rc18
     pullPolicy: IfNotPresent
     pullSecrets: []
   busybox: