diff --git a/.github/workflows/rust-multiplatform.yml b/.github/workflows/rust-multiplatform.yml
index 33e246dd7..a05909a44 100644
--- a/.github/workflows/rust-multiplatform.yml
+++ b/.github/workflows/rust-multiplatform.yml
@@ -115,14 +115,18 @@ jobs:
         # STEP1A_REQUIRE_GPU=1 on a known-good GPU runner to fail hard.
         run: cargo test --workspace --target ${{ matrix.target }}
       - name: Test (host, macOS / Windows)
+        if: matrix.cross == false && matrix.check_only != true && runner.os != 'Linux'
+        run: cargo test --workspace --exclude op-host-desktop --target ${{ matrix.target }}
+      - name: Test op-host-desktop (host, macOS / Windows, serialized)
         if: matrix.cross == false && matrix.check_only != true && runner.os != 'Linux'
         # op-host-desktop's tests build native NativeBackends (skia /
         # DirectWrite fonts); across cargo's parallel test-worker threads this
-        # segfaults on the Windows runner (STATUS_ACCESS_VIOLATION). Split it
-        # out and serialize with --test-threads=1 (matches rust-check.yml).
-        run: |
-          cargo test --workspace --exclude op-host-desktop --target ${{ matrix.target }}
-          cargo test -p op-host-desktop --target ${{ matrix.target }} -- --test-threads=1
+        # segfaults on the Windows runner (STATUS_ACCESS_VIOLATION). Run
+        # single-threaded (matches rust-check.yml). A SEPARATE step — not a
+        # second line in the step above — because Windows runs multi-line
+        # run: blocks under PowerShell, which only fails on the LAST command's
+        # exit code and would mask a failure in the workspace test above.
+        run: cargo test -p op-host-desktop --target ${{ matrix.target }} -- --test-threads=1
       # Desktop binary artifact upload is intentionally not wired here yet.
       # The real desktop binary lives in the `op-host-desktop` crate; a
       # build + upload step can be added once release packaging is finalized.