diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0fb4a7dc..f9bb2c6b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -330,6 +330,14 @@ jobs:
       - name: Run library tests with the tick-body profiler enabled
         run: cargo test --lib --features profiling
 
+      # Debug-only helpers (anything behind #[cfg(debug_assertions)]) vanish in
+      # a release build, so a test calling one without the same gate breaks a
+      # build no other job performs: every run above compiles the test target
+      # in debug. Compile it in release too, without running it — the point is
+      # that it builds at all. Mirrored in testing/ci-local.sh.
+      - name: Compile the library tests in release mode
+        run: cargo test --release --lib --no-run
+
 # ─────────────────────────────────────────────────────────────────────────────
 # Job 2b – Unit tests (macOS)
 # ─────────────────────────────────────────────────────────────────────────────
diff --git a/src/node/tests/unit.rs b/src/node/tests/unit.rs
index 12b0ff7b..5bc4ca87 100644
--- a/src/node/tests/unit.rs
+++ b/src/node/tests/unit.rs
@@ -3977,7 +3977,10 @@ fn handshake_presence_tracks_the_carrier_not_the_noise_handles() {
             "rekey-msg2 discriminator: {when}"
         );
         // Fires the live-carrier coherence assertion; a machine that had gone
-        // invisible would panic here rather than fail an assert_eq above.
+        // invisible would panic here rather than fail an assert_eq above. The
+        // helper only exists in debug builds, so the rest of this test carries
+        // on without it under `--release`.
+        #[cfg(debug_assertions)]
         node.debug_assert_peer_maps_coherent();
     };
 
diff --git a/testing/ci-local.sh b/testing/ci-local.sh
index 9b097be5..5a4b6a4f 100755
--- a/testing/ci-local.sh
+++ b/testing/ci-local.sh
@@ -603,6 +603,20 @@ run_tests() {
     else
         record "unit-tests-profiling" 1
     fi
+
+    # Debug-only helpers (anything behind #[cfg(debug_assertions)]) vanish in a
+    # release build, so a test calling one without the same gate breaks a build
+    # nothing here ever performs: every run above compiles the test target in
+    # debug. Compile it in release too, without running it — the point is that
+    # it builds at all. Mirrored in .github/workflows/ci.yml; check-ci-parity.sh
+    # compares integration suites only and would not catch a stage added to one
+    # runner and not the other.
+    info "cargo test --release --lib --no-run"
+    if cargo test --release --lib --no-run 2>&1; then
+        record "release-test-compile" 0
+    else
+        record "release-test-compile" 1
+    fi
 }
 
 # ── Stage 3: Integration Tests ─────────────────────────────────────────────