diff --git a/infra/k8s/argo/train-template.yaml b/infra/k8s/argo/train-template.yaml
index 6f1e4fd56..4fcd1c46a 100644
--- a/infra/k8s/argo/train-template.yaml
+++ b/infra/k8s/argo/train-template.yaml
@@ -166,12 +166,21 @@ spec:
           # pods and commits (cargo's incremental cache is invalidated by
           # git checkout mtime touches — sccache is content-hash keyed so it
           # isn't). Binary assumed present in ci-builder image.
+          #
+          # CARGO_INCREMENTAL=0 is required to make sccache effective:
+          # the project's Cargo.toml / .cargo/config.toml set
+          # `incremental = true`, which emits per-query save-analysis
+          # artifacts that sccache does not cache. Turning incremental off
+          # lets rustc emit pure object output that sccache hashes
+          # uniformly — same source + same args → cache hit.
           - name: RUSTC_WRAPPER
             value: sccache
           - name: SCCACHE_DIR
             value: /cargo-target/sccache
           - name: SCCACHE_CACHE_SIZE
             value: "40G"
+          - name: CARGO_INCREMENTAL
+            value: "0"
           - name: GITLAB_PAT
             valueFrom:
               secretKeyRef: